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Sample records for abb lummus crest

  1. Lummus clean fuels from coal

    SciTech Connect

    Gantt, J.E.; Hefferan, J.K.; Chorba, W.F.; Schachtschneider, A.B.; Schulze, J.R.

    1980-12-01

    This report compares two direct, catalytic, hydroliquefaction processes - H-Coal and Lummus Clean Fuels From Coal (LCFFC). These processes are compared for two sets of operating conditions. In the first, the reactors are operated to produce a product suitable for use as fuel oil (fuel oil mode). In the second, the operating conditions are more severe, so the resulting product slates more closely resemble crude oil (syncrude mode). The comparisons are performed using conceptual designs based on single point run data, with a design basis of 25,000 tpd (moisture-free basis) of Illinois No. 6 coal. Although all cost comparisons are well within the estimated 25% accuracy of the estimates, LCFFC shows generally lower costs. Three types of economic evaluation are performed: computation of internal rate of return (IRR) with product values set to estimated market value, computation of overall average product cost ($/MM Btu) with the discount rate set at 20%, and calculation of average product cost with naphtha credited at estimated market value and the discount rate set at 20%. H-Coal has a lower cost only in the fuel oil mode analysis with naphtha valued at market price. The processes are also compared with respect to the potential for commercialization and anticipated operability differences. It is concluded that the lower hydrogen content of LCFFC product may offset its advantage of lower cost if it is used as refinery feed, and that the design of the LCFFC reactor may make it harder to control. Suggestions for future research are presented.

  2. ABB Combustion Engineering nuclear technology

    SciTech Connect

    Matzie, R.A.

    1994-12-31

    The activities of ABB Combustion Engineering in the design and construction of nuclear systems and components are briefly reviewed. ABB Construction Engineering continues to improve the design and design process for nuclear generating stations. Potential improvements are evaluated to meet new requirements both of the public and the regulator, so that the designs meet the highest standards worldwide. Advancements necessary to meet market needs and to ensure the highest level of performance in the future will be made.

  3. Korean order latest ABB project in Asia

    SciTech Connect

    1996-07-01

    ABB, in various incarnations, has been active in Asia from the beginning of the century. The new power plant in Korea represents a major commitment on the part of Korea Electric Power Corporation to ABB`s newest technology - the advanced sequential combustion gas turbine. For installation in Poryong, Korea, KEPCO has ordered a 2000MW combined-cycle power plant based on eight of ABB`s new GT24 gas turbines. This paper describes the project and specifications.

  4. ABB: active bandwidth broker

    NASA Astrophysics Data System (ADS)

    Wong, Kason; Law, Eddie

    2001-07-01

    In this paper, we shall discuss a novel design on the policy-based management for the Internet. This design deploys the concept of active networking. As opposed to the traditional network design, active network empowers network node with the ability to manipulate data and program code in packets, and configure the network properties according to the needs of different applications. The policy-based management can control network routers in order to realize end-to-end Quality of Service (QoS), such as differentiated and integrated services, across the Internet. For the moment, the Internet Engineering Task Force (IETF) has defined the framework of the policy-based management. It employs a simple client/server model that uses Common Open Policy Service (COPS) protocol to facilitate policy management and control. Our design of Active Bandwidth Broker (ABB) belongs to an active application. Our goals are to distribute centralized workload of the policy-based management over multiple active nodes in the active networks, introduce mobility of the bandwidth brokers, and allows load sharing to the policy-based management. This results a network-wide intelligent, highly available, and consistent QoS control that allows performance protection for voice, video and Internet business application while reducing costs for growing networks.

  5. Crested caracara

    USGS Publications Warehouse

    Ellis, D.H.; Smith, D.G.; Whaley, W.H.; Ellis, C.H.

    1988-01-01

    The crested caracara's range extends from the southern United States south to Tierra del Fuego. Although the caracara has been recorded in all of the southwestern states, it occurs regularly only in southern Arizona and central, southern and coastal Texas. Its distribution is closely linked to the availability of carrion. Throughout its range, thecaracara is associated with open habitats such as desertscrub, grassland and savanna. Nesting pairs usually produce one brood each breeding season, which extends from December through August. Eggs are laid from March into early June and clutch size averages two to three eggs. Young fledge in June and July and may remain with the adults for several weeks. Management recommendations for the crested caracara include clarifying its status in the Southwest. using supplemental feeding and modifying habitats to encourage recolonization of previously occupied areas and movement into new areas.

  6. The ABB transformer monitoring system

    SciTech Connect

    Claiborne, C.; Gorman, M.; Petrie, E.M.

    1996-03-01

    ABB is currently developing a transformer monitoring system that will continuously perform multiple gas-in-oil and partial discharge analyses. The new monitoring system is designed to be simple and reliable. It can be applied to new units or easily retrofitted to existing transformers. The parameters that are monitored are those that are most commonly evaluated when diagnosing the condition of a power transformer. A multiple gas monitor can selectively detect and measure hydrogen, carbon monoxide, and the combination of methane and ethane. The partial discharge monitor employs an electrical method to detect partial discharges that originate from sources only within the transformer. Prototype systems will be field tested in 1995.

  7. 76 FR 8785 - ABB Inc.; License Amendment Request for Decommissioning of the ABB Inc., Combustion Engineering...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... NRC E-Filing rule (72 FR 49139, August 28, 2007). The E-Filing process requires participants to submit... COMMISSION ABB Inc.; License Amendment Request for Decommissioning of the ABB Inc., Combustion Engineering... concentration guideline levels at its Combustion Engineering site located in Windsor, Connecticut. DATES:...

  8. Creative Copper Crests

    ERIC Educational Resources Information Center

    Knab, Thomas

    2011-01-01

    In this article, the author discusses how to create an art activity that would link the computer-created business cards of fourth-grade students with an upcoming school-wide medieval event. Creating family crests from copper foil would be a great connection, since they, like business cards, are an individual's way to identify themselves to others.…

  9. Neural Crest Lineage Segregation

    PubMed Central

    Luan, X.; Dangaria, S.; Ito, Y.; Walker, C.G.; Jin, T.; Schmidt, M.K.; Galang, M.T.; Druzinsky, R.

    2009-01-01

    During the recent decade, the periodontal attachment apparatus has become one of the premier areas of the body for the development of novel tissue-engineering strategies. In the present review, we describe a developmental biology approach to characterize current concepts in periodontal regeneration and to discuss strategies for future applications in periodontal therapies. To decipher the developmental make-up of the periodontal region, we have followed the path of the migratory neural crest, since it gives rise to periodontal progenitor tissues, which in turn are subjected to the influence of diverse craniofacial extracellular matrices and peptide growth factors. Based on this developmental perspective, we have conducted a systematic analysis of the factors, progenitor cells, and matrices used in current periodontal tissue-engineering approaches. We propose that the developmental history of a tissue is a highly instructive design template for the discovery of novel bioengineering tools and approaches. PMID:19767574

  10. Incremental evolution of the neural crest, neural crest cells and neural crest-derived skeletal tissues

    PubMed Central

    Hall, Brian K; Gillis, J Andrew

    2013-01-01

    Urochordates (ascidians) have recently supplanted cephalochordates (amphioxus) as the extant sister taxon of vertebrates. Given that urochordates possess migratory cells that have been classified as ‘neural crest-like’– and that cephalochordates lack such cells – this phylogenetic hypothesis may have significant implications with respect to the origin of the neural crest and neural crest-derived skeletal tissues in vertebrates. We present an overview of the genes and gene regulatory network associated with specification of the neural crest in vertebrates. We then use these molecular data – alongside cell behaviour, cell fate and embryonic context – to assess putative antecedents (latent homologues) of the neural crest or neural crest cells in ascidians and cephalochordates. Ascidian migratory mesenchymal cells – non-pigment-forming trunk lateral line cells and pigment-forming ‘neural crest-like cells’ (NCLC) – are unlikely latent neural crest cell homologues. Rather, Snail-expressing cells at the neural plate of border of urochordates and cephalochordates likely represent the extent of neural crest elaboration in non-vertebrate chordates. We also review evidence for the evolutionary origin of two neural crest-derived skeletal tissues – cartilage and dentine. Dentine is a bona fide vertebrate novelty, and dentine-secreting odontoblasts represent a cell type that is exclusively derived from the neural crest. Cartilage, on the other hand, likely has a much deeper origin within the Metazoa. The mesodermally derived cellular cartilages of some protostome invertebrates are much more similar to vertebrate cartilage than is the acellular ‘cartilage-like’ tissue in cephalochordate pharyngeal arches. Cartilage, therefore, is not a vertebrate novelty, and a well-developed chondrogenic program was most likely co-opted from mesoderm to the neural crest along the vertebrate stem. We conclude that the neural crest is a vertebrate novelty, but that neural

  11. ABB Combustion Engineering`s nuclear experience and technologies

    SciTech Connect

    Matzie, R.A.

    1994-12-31

    ABB Combustion Engineering`s nuclear experience and technologies are outlined. The following topics are discussed: evolutionary approach using proven technology, substantial improvement to plant safety, utility perspective up front in developing design, integrated design, competitive plant cost, operability and maintainability, standardization, and completion of US NRC technical review.

  12. ABB`s LEBS technologies: Practical solutions for controlling air emissions and increasing efficiency

    SciTech Connect

    Regan, J.W.; Hein, R.J. von; Wesnor, J.D.

    1997-07-01

    When evaluating candidate technologies for controlling air emissions and increasing thermal efficiency the main criteria used by most utility and industrial decision makers are: (1) total installed cost of the system and (2) the impact the system may have on O&M costs, on unit forced outage rate/availability and on unit efficiency. Generally speaking, simpler is better. Designs which have fewer and simpler process steps and components will almost always have lower first cost, reduced maintenance cost, reduced operating labor cost, and fewer forced outages/higher availability. This paper describes technologies developed for the control of NO{sub x}, SO{sub 2} and particulate emissions and for increased efficiency in the designs prepared by the ABB team for the U.S. Department of Energy (DOE) project titled {open_quote}Engineering Development of Advanced Coal-Fired Low-Emission Boiler Systems{close_quote} (LEBS). The primary objectives of the LEBS project are to reduce emissions to approximately one-fifth of current new source performance standards and to increase efficiency, all without increasing the cost of electricity. The project encompasses the use of Pulverized coal combustion and development of near-term technologies. The team selected an advanced low-NO{sub x} firing system and an advanced dry scrubber system to meet the emissions objectives and a Kalina cycle to achieve the efficiency and cost of electricity objectives. The development and design of these technologies, witch are suited to new or retrofit applications, are described in the paper.

  13. Cleft Rhinoplasty- Columellar lengthening prolabial reconstruction with Abbe flap

    PubMed Central

    Balaji, S. M.

    2016-01-01

    Introduction: A single center's experience of correction of cleft lip/palate associated rhinoplasty using Abbe flap is relatively rare in literature. The outcome and perception of the Abbe flap for cleft rhinoplasty at patient, surgeons, and patient's caregiver level have not been found in literature. This manuscript aims to address this lacuna through the use of rhinoplasty outcomes evaluation questionnaire (ROEQ). Materials and Methods: A retrospective analysis of preoperative satisfaction and prospective analysis of postoperative satisfaction of patients who underwent cleft rhinoplasty were carried out using ROEQ. This was used twice measuring the pre- and post-operative periods. Results: Twenty-one cases of bilateral cleft lip and palate who had earlier undergone (0.5–3 years back) cleft rhinoplasty and lip revision with Abbe's flap formed the study group. The mean age of the 21 subjects was 22.87 ± 4.23 years. There were 13 males and 8 females forming the study group. The mean presurgical ROEQ score was 19.8 ± 11.2, while the postsurgical score was 78.5 ± 21.2. This difference was statistically significant (P = 0.001). The difference in score between the time period was 58.7%. Discussion: From the ROEQ and other qualitative parameters, it is possible to demonstrate the impact of Abbe flap for cleft rhinoplasty and its impact on the quality of life of patients. Most of the patients and caregivers believed that this approach achieved a good or excellent postoperative result. The biological and operators factors behind such a success are discussed in light of previously published literature.

  14. Neural crest migration: trailblazing ahead.

    PubMed

    Kulesa, Paul M; McLennan, Rebecca

    2015-01-01

    Embryonic cell migration patterns are amazingly complex in the timing and spatial distribution of cells throughout the vertebrate landscape. However, advances in in vivo visualization, cell interrogation, and computational modeling are extracting critical features that underlie the mechanistic nature of these patterns. The focus of this review highlights recent advances in the study of the highly invasive neural crest cells and their migratory patterns during embryonic development. We discuss these advances within three major themes and include a description of computational models that have emerged to more rapidly integrate and test hypothetical mechanisms of neural crest migration. We conclude with technological advances that promise to reveal new insights and help translate results to human neural crest-related birth defects and metastatic cancer. PMID:25705385

  15. Neural crest migration: trailblazing ahead

    PubMed Central

    McLennan, Rebecca

    2015-01-01

    Embryonic cell migration patterns are amazingly complex in the timing and spatial distribution of cells throughout the vertebrate landscape. However, advances in in vivo visualization, cell interrogation, and computational modeling are extracting critical features that underlie the mechanistic nature of these patterns. The focus of this review highlights recent advances in the study of the highly invasive neural crest cells and their migratory patterns during embryonic development. We discuss these advances within three major themes and include a description of computational models that have emerged to more rapidly integrate and test hypothetical mechanisms of neural crest migration. We conclude with technological advances that promise to reveal new insights and help translate results to human neural crest-related birth defects and metastatic cancer. PMID:25705385

  16. The Neural Crest in Cardiac Congenital Anomalies

    PubMed Central

    Keyte, Anna; Hutson, Mary Redmond

    2012-01-01

    This review discusses the function of neural crest as they relate to cardiovascular defects. The cardiac neural crest cells are a subpopulation of cranial neural crest discovered nearly 30 years ago by ablation of premigratory neural crest. The cardiac neural crest cells are necessary for normal cardiovascular development. We begin with a description of the crest cells in normal development, including their function in remodeling the pharyngeal arch arteries, outflow tract septation, valvulogenesis, and development of the cardiac conduction system. The cells are also responsible for modulating signaling in the caudal pharynx, including the second heart field. Many of the molecular pathways that are known to influence specification, migration, patterning and final targeting of the cardiac neural crest cells are reviewed. The cardiac neural crest cells play a critical role in the pathogenesis of various human cardiocraniofacial syndromes such as DiGeorge, Velocardiofacial, CHARGE, Fetal Alcohol, Alagille, LEOPARD, and Noonan syndromes, as well as Retinoic Acid Embryopathy. The loss of neural crest cells or their dysfunction may not always directly cause abnormal cardiovascular development, but are involved secondarily because crest cells represent a major component in the complex tissue interactions in the head, pharynx and outflow tract. Thus many of the human syndromes linking defects in the heart, face and brain can be better understood when considered within the context of a single cardiocraniofacial developmental module with the neural crest being a key cell type that interconnects the regions. PMID:22595346

  17. Calculating the Weather: Deductive Reasoning and Disciplinary "Telos" in Cleveland Abbe's Rhetorical Transformation of Meteorology

    ERIC Educational Resources Information Center

    Majdik, Zoltan P.; Platt, Carrie Anne; Meister, Mark

    2011-01-01

    This paper explores the rhetorical basis of a major paradigm change in meteorology, from a focus on inductive observation to deductive, mathematical reasoning. Analysis of Cleveland Abbe's "The Physical Basis of Long-Range Weather Forecasts" demonstrates how in his advocacy for a new paradigm, Abbe navigates the tension between piety to tradition…

  18. Chemotaxis during neural crest migration.

    PubMed

    Shellard, Adam; Mayor, Roberto

    2016-07-01

    Chemotaxis refers to the directional migration of cells towards external, soluble factors along their gradients. It is a process that is used by many different cell types during development for tissue organisation and the formation of embryonic structures, as well as disease like cancer metastasis. The neural crest (NC) is a multipotent, highly migratory cell population that contribute to a range of tissues. It has been hypothesised that NC migration, at least in part, is reliant on chemotactic signals. This review will explore the current evidence for proposed chemoattractants of NC cells, and outline mechanisms for the chemotactic response of the NC to them. PMID:26820523

  19. The neural crest: a versatile organ system.

    PubMed

    Zhang, Dongcheng; Ighaniyan, Samiramis; Stathopoulos, Lefteris; Rollo, Benjamin; Landman, Kerry; Hutson, John; Newgreen, Donald

    2014-09-01

    The neural crest is the name given to the strip of cells at the junction between neural and epidermal ectoderm in neurula-stage vertebrate embryos, which is later brought to the dorsal neural tube as the neural folds elevate. The neural crest is a heterogeneous and multipotent progenitor cell population whose cells undergo EMT then extensively and accurately migrate throughout the embryo. Neural crest cells contribute to nearly every organ system in the body, with derivatives of neuronal, glial, neuroendocrine, pigment, and also mesodermal lineages. This breadth of developmental capacity has led to the neural crest being termed the fourth germ layer. The neural crest has occupied a prominent place in developmental biology, due to its exaggerated migratory morphogenesis and its remarkably wide developmental potential. As such, neural crest cells have become an attractive model for developmental biologists for studying these processes. Problems in neural crest development cause a number of human syndromes and birth defects known collectively as neurocristopathies; these include Treacher Collins syndrome, Hirschsprung disease, and 22q11.2 deletion syndromes. Tumors in the neural crest lineage are also of clinical importance, including the aggressive melanoma and neuroblastoma types. These clinical aspects have drawn attention to the selection or creation of neural crest progenitor cells, particularly of human origin, for studying pathologies of the neural crest at the cellular level, and also for possible cell therapeutics. The versatility of the neural crest lends itself to interlinked research, spanning basic developmental biology, birth defect research, oncology, and stem/progenitor cell biology and therapy. PMID:25227568

  20. Crest lines for surface segmentation and flattening.

    PubMed

    Stylianou, Georgios; Farin, Gerald

    2004-01-01

    We present a method for extracting feature curves called crest lines from a triangulated surface. Then, we calculate the geodesic Voronoi diagram of crest lines to segment the surface into several regions. Afterward, barycentric surface flattening using theory from graph embeddings is implemented and, using the Geodesic Voronoi diagram, we develop a faster surface flattening algorithm. PMID:15794136

  1. On Sharp-Crested Gravity Waves

    NASA Astrophysics Data System (ADS)

    Lukomsky, Vasyl; Gandzha, Ivan; Tsekhmister, Yaroslav; Chalyi, Alexander

    2004-11-01

    In the framework of the canonical model of hydrodynamics, where fluid is assumed to be ideal and incompressible, waves are potential, two-dimensional, steady, and symmetric, we provide numerical evidence for the likely existence of sharp-crested gravity waves different from the well-known limiting Stokes wave with a 120^rc corner at the crest. To this end, the physical plane methods of ordinary and fractional Fourier approximations and the inverse plane Michell method were used. They all reveal new approximate irregular solutions that seem to represent a family of sharp-crested gravity waves with lesser amplitude (the through-to-crest height) than that of the limiting Stokes wave. Furthermore, Michell's method demonstrates the existence of a new family of sharp-crested subharmonic waves. We also provide a numerical justification for the conjecture of Grant that the 120^rc singularity of the limiting wave is formed from several coalescing 90^rc singularities.

  2. Neural crest contributions to the lamprey head

    NASA Technical Reports Server (NTRS)

    McCauley, David W.; Bronner-Fraser, Marianne

    2003-01-01

    The neural crest is a vertebrate-specific cell population that contributes to the facial skeleton and other derivatives. We have performed focal DiI injection into the cranial neural tube of the developing lamprey in order to follow the migratory pathways of discrete groups of cells from origin to destination and to compare neural crest migratory pathways in a basal vertebrate to those of gnathostomes. The results show that the general pathways of cranial neural crest migration are conserved throughout the vertebrates, with cells migrating in streams analogous to the mandibular and hyoid streams. Caudal branchial neural crest cells migrate ventrally as a sheet of cells from the hindbrain and super-pharyngeal region of the neural tube and form a cylinder surrounding a core of mesoderm in each pharyngeal arch, similar to that seen in zebrafish and axolotl. In addition to these similarities, we also uncovered important differences. Migration into the presumptive caudal branchial arches of the lamprey involves both rostral and caudal movements of neural crest cells that have not been described in gnathostomes, suggesting that barriers that constrain rostrocaudal movement of cranial neural crest cells may have arisen after the agnathan/gnathostome split. Accordingly, neural crest cells from a single axial level contributed to multiple arches and there was extensive mixing between populations. There was no apparent filling of neural crest derivatives in a ventral-to-dorsal order, as has been observed in higher vertebrates, nor did we find evidence of a neural crest contribution to cranial sensory ganglia. These results suggest that migratory constraints and additional neural crest derivatives arose later in gnathostome evolution.

  3. PAX transcription factors in neural crest development.

    PubMed

    Monsoro-Burq, Anne H

    2015-08-01

    The nine vertebrate PAX transcription factors (PAX1-PAX9) play essential roles during early development and organogenesis. Pax genes were identified in vertebrates using their homology with the Drosophila melanogaster paired gene DNA-binding domain. PAX1-9 functions are largely conserved throughout vertebrate evolution, in particular during central nervous system and neural crest development. The neural crest is a vertebrate invention, which gives rise to numerous derivatives during organogenesis, including neurons and glia of the peripheral nervous system, craniofacial skeleton and mesenchyme, the heart outflow tract, endocrine and pigment cells. Human and mouse spontaneous mutations as well as experimental analyses have evidenced the critical and diverse functions of PAX factors during neural crest development. Recent studies have highlighted the role of PAX3 and PAX7 in neural crest induction. Additionally, several PAX proteins - PAX1, 3, 7, 9 - regulate cell proliferation, migration and determination in multiple neural crest-derived lineages, such as cardiac, sensory, and enteric neural crest, pigment cells, glia, craniofacial skeleton and teeth, or in organs developing in close relationship with the neural crest such as the thymus and parathyroids. The diverse PAX molecular functions during neural crest formation rely on fine-tuned modulations of their transcriptional transactivation properties. These modulations are generated by multiple means, such as different roles for the various isoforms (formed by alternative splicing), or posttranslational modifications which alter protein-DNA binding, or carefully orchestrated protein-protein interactions with various co-factors which control PAX proteins activity. Understanding these regulations is the key to decipher the versatile roles of PAX transcription factors in neural crest development, differentiation and disease. PMID:26410165

  4. Neural crest development in fetal alcohol syndrome.

    PubMed

    Smith, Susan M; Garic, Ana; Flentke, George R; Berres, Mark E

    2014-09-01

    Fetal alcohol spectrum disorder (FASD) is a leading cause of neurodevelopmental disability. Some affected individuals possess distinctive craniofacial deficits, but many more lack overt facial changes. An understanding of the mechanisms underlying these deficits would inform their diagnostic utility. Our understanding of these mechanisms is challenged because ethanol lacks a single receptor when redirecting cellular activity. This review summarizes our current understanding of how ethanol alters neural crest development. Ample evidence shows that ethanol causes the "classic" fetal alcohol syndrome (FAS) face (short palpebral fissures, elongated upper lip, deficient philtrum) because it suppresses prechordal plate outgrowth, thereby reducing neuroectoderm and neural crest induction and causing holoprosencephaly. Prenatal alcohol exposure (PAE) at premigratory stages elicits a different facial appearance, indicating FASD may represent a spectrum of facial outcomes. PAE at this premigratory period initiates a calcium transient that activates CaMKII and destabilizes transcriptionally active β-catenin, thereby initiating apoptosis within neural crest populations. Contributing to neural crest vulnerability are their low antioxidant responses. Ethanol-treated neural crest produce reactive oxygen species and free radical scavengers attenuate their production and prevent apoptosis. Ethanol also significantly impairs neural crest migration, causing cytoskeletal rearrangements that destabilize focal adhesion formation; their directional migratory capacity is also lost. Genetic factors further modify vulnerability to ethanol-induced craniofacial dysmorphology and include genes important for neural crest development, including shh signaling, PDFGA, vangl2, and ribosomal biogenesis. Because facial and brain development are mechanistically and functionally linked, research into ethanol's effects on neural crest also informs our understanding of ethanol's CNS pathologies. PMID

  5. Statistics of wave crests in storms

    NASA Astrophysics Data System (ADS)

    Tayfun, M. A.

    2003-04-01

    Sea waves generated in severe storms are nonlinear and display a vertically skewed profile in terms of higher more pointed crests and shallower more rounded troughs. In particular, large waves tend to have extremely large crests. A statistical description of such large crest levels has theoretical and practical importance. At present, no exact theory exists for describing the statistical distribution of crest heights of nonlinear waves. This study explores further a recently developed least-upper-bound (lub) distribution for crest heights of large waves within the context of second-order nonlinear wave theory. Preliminary comparisons of the lub distribution and associated statistics to extreme waves from hurricane Camille in the Gulf of Mexico in 1969 have been favorable. But, the measurements used in these comparisons were limited in terms of their sample sizes and infrequent sampling rates. Thus, establishing the relative validity of the lub theory warrants further comparisons with larger sample populations and accurate measurements of storm waves. This study first presents a brief overview of the underlying nonlinear lub wave-crest model, the salient properties and implications of the associated probability distributions and statistics. The theoretical results are then compared with Marex wave data collected by Shell E &P Technology at the Tern platform in the northen North Sea between the Shetland Islands and Norway. The measurements have a sampling rate of 5.12 Hz. The sample exceedance distributions and statistics such as the mean of the highest 1/n-th crest levels derived from a three-hour segment of these measurements are compared with the theoretical predictions based on the lub theory. As in the previous case of the Camille data, comparisons are very favorable and clearly confirm the validity and usefulness of the lub theory for describing the statistics of large wave crests.

  6. Neural Crest Development in Fetal Alcohol Syndrome

    PubMed Central

    Smith, Susan M.; Garic, Ana; Flentke, George R.; Berres, Mark E.

    2016-01-01

    Fetal alcohol spectrum disorder (FASD) is a leading cause of neurodevelopmental disability. Some affected individuals possess distinctive craniofacial deficits, but many more lack overt facial changes. An understanding of the mechanisms underlying these deficits would inform their diagnostic utility. Our understanding of these mechanisms is challenged because ethanol lacks a single receptor when redirecting cellular activity. This review summarizes our current understanding of how ethanol alters neural crest development. Ample evidence shows that ethanol causes the “classic” fetal alcohol syndrome (FAS) face (short palpebral fissures, elongated upper lip, deficient philtrum) because it suppresses prechordal plate outgrowth, thereby reducing neuroectoderm and neural crest induction and causing holoprosencephaly. Prenatal alcohol exposure (PAE) at premigratory stages elicits a different facial appearance, indicating FASD may represent a spectrum of facial outcomes. PAE at this premigratory period initiates a calcium transient that activates CaMKII and destabilizes transcriptionally active β-catenin, thereby initiating apoptosis within neural crest populations. Contributing to neural crest vulnerability are their low antioxidant responses. Ethanol-treated neural crest produce reactive oxygen species, and free radical scavengers attenuate their production and prevent apoptosis. Ethanol also significantly impairs neural crest migration, causing cytoskeletal rearrangements that destabilize focal adhesion formation; their directional migratory capacity is also lost. Genetic factors further modify vulnerability to ethanol-induced craniofacial dysmorphology, and include genes important for neural crest development including shh signaling, PDFGA, vangl2, and ribosomal biogenesis. Because facial and brain development are mechanistically and functionally linked, research into ethanol’s effects on neural crest also informs our understanding of ethanol’s CNS pathologies

  7. [Neural crest disorders and Hirschsprung's disease].

    PubMed

    Espinosa, R; Alonso Calderón, J L

    2009-01-01

    The term Neurocristopathy describes a group of conditions caused by aberrations in growth, migration and differentiation of neural crest cells. In this sense, Hirschsprung's disease is a consequence of a failure in neural crest cells migration to distal intestine and in consequence it is considered to be part of neurocristopathy concept. This concept includes several diseases that can present either alone or in combination as a syndrome. We present 4 patients suffering Hirschsprung's disease associated with others neurocristopathies: 1 Waardenburg's syndrome, 1 congenital central hypoventilation syndrome or Ondine's curse, 1 ganglioneuroblastoma and 1 patient with bilateral sensory deafness. PMID:19323078

  8. Factors controlling cardiac neural crest cell migration

    PubMed Central

    Hutson, Mary R

    2010-01-01

    Cardiac neural crest cells originate as part of the postotic caudal rhombencephalic neural crest stream. Ectomesenchymal cells in this stream migrate to the circumpharyngeal ridge and then into the caudal pharyngeal arches where they condense to form first a sheath and then the smooth muscle tunics of the persisting pharyngeal arch arteries. A subset of the cells continues migrating into the cardiac outflow tract where they will condense to form the aorticopulmonary septum. Cell signaling, extracellular matrix and cell-cell contacts are all critical for the initial migration, pauses, continued migration and condensation of these cells. This Review elucidates what is currently known about these factors. PMID:20890117

  9. Effect of Impact Damage on the Fatigue Response of TiAl Alloy-ABB-2

    NASA Technical Reports Server (NTRS)

    Draper, S. L.; Lerch, B. A.; Pereira, J. M.; Nathal, M. V.; Nazmy, M. Y.; Staubli, M.; Clemens, D. R.

    2001-01-01

    The ability of gamma-TiAl to withstand potential foreign or domestic object damage is a technical risk to the implementation of gamma-TiAl in low pressure turbine (LPT) blade applications. In the present study, the impact resistance of TiAl alloy ABB-2 was determined and compared to the impact resistance of Ti(48)Al(2)Nb(2)Cr. Specimens were impacted with four different impact conditions with impact energies ranging from 0.22 to 6.09 J. After impacting, the impact damage was characterized by crack lengths on both the front and backside of the impact. Due to the flat nature of gamma-TiAl's S-N (stress vs. cycles to failure) curve, step fatigue tests were used to determine the fatigue strength after impacting. Impact damage increased with increasing impact energy and led to a reduction in the fatigue strength of the alloy. For similar crack lengths, the fatigue strength of impacted ABB-2 was similar to the fatigue strength of impacted Ti(48)Al(2)Nb(2)Cr, even though the tensile properties of the two alloys are significantly different. Similar to Ti(48)Al(2)Nb(2)Cr, ABB-2 showed a classical mean stress dependence on fatigue strength. The fatigue strength of impacted ABB-2 could be accurately predicted using a threshold analysis.

  10. Project CREST, Gainesville, Florida. An Exemplary Project.

    ERIC Educational Resources Information Center

    DeJong, William; Stewart, Carolyn

    This manual describes Project CREST (Clinical Regional Support Teams), a community project established in Gainesville, Florida, to supplement State probation services by providing professional counseling to delinquent youth. The project uses a dual treatment approach in which, on the one hand, probation officers impose restrictions, while on the…

  11. Modified osteomyocutaneous iliac crest flaps transplantation.

    PubMed

    Liu, Jun; Song, Dajiang; Li, Jinsong; Xu, Jian; Lv, Hongbin

    2015-04-01

    The paper aims to improve the operative technique of osteomyocutaneous iliac crest flap harvesting, further minimise morbidity of donor site, and improve the effect of recipient site reconstruction. From March 2005 to March 2011, 55 cases of osteomyocutaneous iliac crest flap harvested by different methods were performed to reconstruct the defects of the extremities. Twenty-nine cases were reconstructed with a traditional deep circumflex iliac artery osteomusculocutaneous flap. Twenty-six cases were repaired with modified osteomyocutaneous iliac crest flaps. In 29 cases with a traditional DCIA osteomusculocutaneous flap, two cases showed the injured lateral femoral cutaneous nerve. Flapnecrosis was significant in two cases. Arterial compromise occurred in one case 5 days after operation completion and led to flap failure. Three flaps developed postoperative venous congestion, but only one flap received re-exploration. In the other two cases, some stitches were removed for decompression. All three flaps survived. In two cases, marginal flap necrosis occurred, but no secondary skin grafting was required. In 26 cases with modified flap transplantation, one case showed the injured lateral femoral cutaneous nerve. All flaps survived totally. Osseous integration was achieved in all 55 cases in 3 ∼ 9 months after operation. The modified osteomyocutaneous iliac crest flap technique enhances flap safety, provides the additional advantages of reducing donor-site morbidity, and improves the recipient-site contour. PMID:25001367

  12. The Health Connection at Cedar Crest College

    ERIC Educational Resources Information Center

    Baker, Kerrie; Boland, Kathleen; Laffey, Joan M.

    2006-01-01

    The mission of Cedar Crest College, an independent women's college, is to provide students with excellent education that is grounded in the liberal arts and informed by humanistic values. In 2003, Student Affairs staff of the school looked closely at those students who were graduating and began to realize that though the college was providing…

  13. 36 CFR 212.21 - Pacific Crest National Scenic Trail.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Pacific Crest National Scenic... AGRICULTURE TRAVEL MANAGEMENT Administration of the Forest Transportation System § 212.21 Pacific Crest National Scenic Trail. The Pacific Crest National Scenic Trail as defined by the National Trails...

  14. 36 CFR 212.21 - Pacific Crest National Scenic Trail.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Pacific Crest National Scenic... AGRICULTURE TRAVEL MANAGEMENT Administration of the Forest Transportation System § 212.21 Pacific Crest National Scenic Trail. The Pacific Crest National Scenic Trail as defined by the National Trails...

  15. 36 CFR 261.20 - Pacific Crest National Scenic Trail.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Pacific Crest National Scenic... AGRICULTURE PROHIBITIONS General Prohibitions § 261.20 Pacific Crest National Scenic Trail. It is prohibited to use a motorized vehicle on the Pacific Crest National Scenic Trail without a...

  16. 36 CFR 212.21 - Pacific Crest National Scenic Trail.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Pacific Crest National Scenic... AGRICULTURE TRAVEL MANAGEMENT Administration of the Forest Transportation System § 212.21 Pacific Crest National Scenic Trail. The Pacific Crest National Scenic Trail as defined by the National Trails...

  17. 36 CFR 212.21 - Pacific Crest National Scenic Trail.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Pacific Crest National Scenic... AGRICULTURE TRAVEL MANAGEMENT Administration of the Forest Transportation System § 212.21 Pacific Crest National Scenic Trail. The Pacific Crest National Scenic Trail as defined by the National Trails...

  18. 36 CFR 261.20 - Pacific Crest National Scenic Trail.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Pacific Crest National Scenic... AGRICULTURE PROHIBITIONS General Prohibitions § 261.20 Pacific Crest National Scenic Trail. It is prohibited to use a motorized vehicle on the Pacific Crest National Scenic Trail without a...

  19. 36 CFR 261.20 - Pacific Crest National Scenic Trail.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Pacific Crest National Scenic... AGRICULTURE PROHIBITIONS General Prohibitions § 261.20 Pacific Crest National Scenic Trail. It is prohibited to use a motorized vehicle on the Pacific Crest National Scenic Trail without a...

  20. 36 CFR 212.21 - Pacific Crest National Scenic Trail.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Pacific Crest National Scenic... AGRICULTURE TRAVEL MANAGEMENT Administration of the Forest Transportation System § 212.21 Pacific Crest National Scenic Trail. The Pacific Crest National Scenic Trail as defined by the National Trails...

  1. 36 CFR 261.20 - Pacific Crest National Scenic Trail.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Pacific Crest National Scenic... AGRICULTURE PROHIBITIONS General Prohibitions § 261.20 Pacific Crest National Scenic Trail. It is prohibited to use a motorized vehicle on the Pacific Crest National Scenic Trail without a...

  2. Carbon storage regulator A (CsrABb) is a repressor of Borrelia burgdorferi flagellin protein FlaB

    PubMed Central

    Sze, Ching Wooen; Morado, Dustin R.; Jun, Liu; Charon, Nyles W.; Hongbin, Xu; Chunhao, Li

    2011-01-01

    SUMMARY The Lyme disease spirochete Borrelia burgdorferi lacks the transcriptional cascade control of flagellar protein synthesis common to other bacteria. Instead, it relies on a post-transcriptional mechanism to control its flagellar synthesis. The underlying mechanism of this control remains elusive. A recent study reported that the increased level of BB0184 (CsrABb; a homolog of carbon storage regulator A) substantially inhibited the accumulation of FlaB, the major flagellin protein of B. burgdorferi. In this report, we deciphered the regulatory role of CsrABb on FlaB synthesis and the mechanism involved by analyzing two mutants, csrABb− (a deletion mutant of csrABb) and csrABb+ (a mutant conditionally over-expressing csrABb). We found that FlaB accumulation was significantly inhibited in csrABb+ but was substantially increased in csrABb−. In contrast, the levels of other flagellar proteins remained unchanged. Cryo-electron tomography and immuno-fluorescence microscopic analyses revealed that the altered synthesis of CsrABb in these two mutants specifically affected flagellar filament length. The leader sequence of flaB transcript contains two conserved CsrA-binding sites, with one of these sites overlapping the Shine-Dalgarno sequence. We found that CsrABb bound to the flaB transcripts via these two binding sites, and this binding inhibited the synthesis of FlaB at the translational level. Taken together, our results indicate that CsrABb specifically regulates the periplasmic flagellar synthesis by inhibiting translation initiation of the flaB transcript. PMID:21999436

  3. The development of the neural crest in the human

    PubMed Central

    O’Rahilly, Ronan; Müller, Fabiola

    2007-01-01

    The first systematic account of the neural crest in the human has been prepared after an investigation of 185 serially sectioned staged embryos, aided by graphic reconstructions. As many as fourteen named topographical subdivisions of the crest were identified and eight of them give origin to ganglia (Table 2). Significant findings in the human include the following. (1) An indication of mesencephalic neural crest is discernible already at stage 9, and trigeminal, facial, and postotic components can be detected at stage 10. (2) Crest was not observed at the level of diencephalon 2. Although pre-otic crest from the neural folds is at first continuous (stage 10), crest-free zones are soon observable (stage 11) in Rh.1, 3, and 5. (3) Emigration of cranial neural crest from the neural folds at the neurosomatic junction begins before closure of the rostral neuropore, and later crest cells do not accumulate above the neural tube. (4) The trigeminal, facial, glossopharyngeal and vagal ganglia, which develop from crest that emigrates before the neural folds have fused, continue to receive contributions from the roof plate of the neural tube after fusion of the folds. (5) The nasal crest and the terminalis-vomeronasal complex are the last components of the cranial crest to appear (at stage 13) and they persist longer. (6) The optic, mesencephalic, isthmic, accessory, and hypoglossal crest do not form ganglia. Cervical ganglion 1 is separated early from the neural crest and is not a Froriep ganglion. (7) The cranial ganglia derived from neural crest show a specific relationship to individual neuromeres, and rhombomeres are better landmarks than the otic primordium, which descends during stages 9–14. (8) Epipharyngeal placodes of the pharyngeal arches contribute to cranial ganglia, although that of arch 1 is not typical. (9) The neural crest from rhombomeres 6 and 7 that migrates to pharyngeal arch 3 and from there rostrad to the truncus arteriosus at stage 12 is identified

  4. Reprogramming of avian neural crest axial identity and cell fate.

    PubMed

    Simoes-Costa, Marcos; Bronner, Marianne E

    2016-06-24

    Neural crest populations along the embryonic body axis of vertebrates differ in developmental potential and fate, so that only the cranial neural crest can contribute to the craniofacial skeleton in vivo. We explored the regulatory program that imbues the cranial crest with its specialized features. Using axial-level specific enhancers to isolate and perform genome-wide profiling of the cranial versus trunk neural crest in chick embryos, we identified and characterized regulatory relationships between a set of cranial-specific transcription factors. Introducing components of this circuit into neural crest cells of the trunk alters their identity and endows these cells with the ability to give rise to chondroblasts in vivo. Our results demonstrate that gene regulatory circuits that support the formation of particular neural crest derivatives may be used to reprogram specific neural crest-derived cell types. PMID:27339986

  5. Use of the Abbe sine condition to quantify alignment aberrations in optical imaging systems

    NASA Astrophysics Data System (ADS)

    Burge, James H.; Zhao, Chunyu; Lu, Sheng Huei

    2010-08-01

    Violation of Abbe's sine condition is well-known to cause coma in axisymmetric imaging systems, and generally any offense against the sine condition (OSC) will cause aberrations that have linear dependence on the field angle. A well-corrected imaging system must obey the Abbe sine condition. A misaligned optical system can have particular forms of the OSC which are evaluated here. The lowest order non-trivial effects of misalignment have quadratic pupil dependence which causes a combination of astigmatism and focus that have linear field dependence. Higher order terms can arise from complex systems, but the effects of misalignment are nearly always dominated by the lowest order effects which can be fully characterized by measuring images on axis and the on-axis offense against the sine condition. By understanding the form of the on-axis images and the OSC, the state of alignment can be determined.

  6. Abbe's number and Cauchy's constant of iodine and selenium doped poly (methylmethacrylate) and polystyrene composites

    SciTech Connect

    Mehta, Sheetal Das, Kallol Keller, Jag Mohan

    2014-04-24

    Poly (methyl methacrylate) / Polystyrene and iodine / selenium hybrid matrixes have been prepared and characterized. Refractive index measurements were done at 390, 535, 590, 635 nm wavelengths. Abbe's number and Cauchy's constants of the iodine / selenium doped poly (methylmethacrylate) and polystyrene samples are being reported. The results also showed that the refractive index of the composite varies non-monotonically with the doping concentration at low iodine concentration or in the region of nanoparticles formation and is also dependent on thermal annealing.

  7. Cardiovascular Development and the Colonizing Cardiac Neural Crest Lineage

    PubMed Central

    Snider, Paige; Olaopa, Michael; Firulli, Anthony B.

    2008-01-01

    Although it is well established that transgenic manipulation of mammalian neural crest-related gene expression and microsurgical removal of premigratory chicken and Xenopus embryonic cardiac neural crest progenitors results in a wide spectrum of both structural and functional congenital heart defects, the actual functional mechanism of the cardiac neural crest cells within the heart is poorly understood. Neural crest cell migration and appropriate colonization of the pharyngeal arches and outflow tract septum is thought to be highly dependent on genes that regulate cell-autonomous polarized movement (i.e., gap junctions, cadherins, and noncanonical Wnt1 pathway regulators). Once the migratory cardiac neural crest subpopulation finally reaches the heart, they have traditionally been thought to participate in septation of the common outflow tract into separate aortic and pulmonary arteries. However, several studies have suggested these colonizing neural crest cells may also play additional unexpected roles during cardiovascular development and may even contribute to a crest-derived stem cell population. Studies in both mice and chick suggest they can also enter the heart from the venous inflow as well as the usual arterial outflow region, and may contribute to the adult semilunar and atrioventricular valves as well as part of the cardiac conduction system. Furthermore, although they are not usually thought to give rise to the cardiomyocyte lineage, neural crest cells in the zebrafish (Danio rerio) can contribute to the myocardium and may have different functions in a species-dependent context. Intriguingly, both ablation of chick and Xenopus premigratory neural crest cells, and a transgenic deletion of mouse neural crest cell migration or disruption of the normal mammalian neural crest gene expression profiles, disrupts ventral myocardial function and/or cardiomyocyte proliferation. Combined, this suggests that either the cardiac neural crest secrete factor/s that

  8. Neural crest cell evolution: how and when did a neural crest cell become a neural crest cell.

    PubMed

    Muñoz, William A; Trainor, Paul A

    2015-01-01

    As vertebrates evolved from protochordates, they shifted to a more predatory lifestyle, and radiated and adapted to most niches of the planet. This process was largely facilitated by the generation of novel vertebrate head structures, which were derived from neural crest cells (NCC). The neural crest is a unique vertebrate cell population that is frequently termed the "fourth germ layer" because it forms in conjunction with the other germ layers and contributes to a diverse array of cell types and tissues including the craniofacial skeleton, the peripheral nervous system, and pigment cells among many other tissues and cell types. NCC are defined by their origin at the neural plate border, via an epithelial-to-mesenchymal transition (EMT), together with multipotency and polarized patterns of migration. These defining characteristics, which evolved independently in the germ layers of invertebrates, were subsequently co-opted through their gene regulatory networks to form NCC in vertebrates. Moreover, recent data suggest that the ability to undergo an EMT was one of the latter features co-opted by NCC. In this review, we discuss the potential origins of NCC and how they evolved to contribute to nearly all tissues and organs throughout the body, based on paleontological evidence together with an evaluation of the evolution of molecules involved in NCC development and their migratory cell paths. PMID:25662256

  9. Cytoplasmic protein methylation is essential for neural crest migration

    PubMed Central

    Vermillion, Katie L.; Lidberg, Kevin A.

    2014-01-01

    As they initiate migration in vertebrate embryos, neural crest cells are enriched for methylation cycle enzymes, including S-adenosylhomocysteine hydrolase (SAHH), the only known enzyme to hydrolyze the feedback inhibitor of trans-methylation reactions. The importance of methylation in neural crest migration is unknown. Here, we show that SAHH is required for emigration of polarized neural crest cells, indicating that methylation is essential for neural crest migration. Although nuclear histone methylation regulates neural crest gene expression, SAHH and lysine-methylated proteins are abundant in the cytoplasm of migratory neural crest cells. Proteomic profiling of cytoplasmic, lysine-methylated proteins from migratory neural crest cells identified 182 proteins, several of which are cytoskeleton related. A methylation-resistant form of one of these proteins, the actin-binding protein elongation factor 1 alpha 1 (EF1α1), blocks neural crest migration. Altogether, these data reveal a novel and essential role for post-translational nonhistone protein methylation during neural crest migration and define a previously unknown requirement for EF1α1 methylation in migration. PMID:24379414

  10. A taxonomic study of crested caracaras (Falconidae)

    USGS Publications Warehouse

    Dove, C.J.; Banks, R.C.

    1999-01-01

    The taxonomic status of the crested caracaras (Caracara spp., Falconidae) has been unsettled for many years. Current sources such as the AOU Check-list recognize a single species that includes three taxa formerly considered distinct, citing observations by Hellmayr and Conover (1949) on two specimens considered to be intermediate. We studied plumage characters and measurements of over 392 museum specimens and found no evidence of clinal change between the northern and southern continental populations. Sixteen specimens from localities near the Amazon River where these two populations sporadically meet exhibit a mosaic of plumage elements from both forms. Measurements of wing chord, bill length, and bill depth indicate that size is positively correlated with latitude north and south of the equator and that females are larger than males in the northern population. These populations do not meet in western South America. We conclude that three biological species can be identified in the crested caracaras: the insular Guadalupe Caracara (Caracara lutosus); and two continental species, Northern (C. cheriway) and Southern caracara (C. plancus), neither of which shows subspecific variation.

  11. Neural crest: The fourth germ layer

    PubMed Central

    Shyamala, K; Yanduri, Sarita; Girish, HC; Murgod, Sanjay

    2015-01-01

    The neural crest cells (NCCs), a transient group of cells that emerges from the dorsal aspect of the neural tube during early vertebrate development has been a fascinating group of cells because of its multipotency, long range migration through embryo and its capacity to generate a prodigious number of differentiated cell types. For these reasons, although derived from the ectoderm, the neural crest (NC) has been called the fourth germ layer. The non neural ectoderm, the neural plate and the underlying mesoderm are needed for the induction and formation of NC cells. Once formed, NC cells start migrating as a wave of cells, moving away from the neuroepithelium and quickly splitting into distinct streams. These migrating NCCs home in to different regions and give rise to plethora of tissues. Umpteen number of signaling molecules are essential for formation, epithelial mesenchymal transition, delamination, migration and localization of NCC. Authors believe that a clear understanding of steps and signals involved in NC formation, migration, etc., may help in understanding the pathogenesis behind cancer metastasis and many other diseases. Hence, we have taken this review to discuss the various aspects of the NC cells. PMID:26604500

  12. Restoring the sagebrush component to crested wheatgrass-dominated communities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Monotypic stands of crested wheatgrass, an introduced grass, occupy vast expanses of the sagebrush steppe. Efforts to improve habitat for sagebrush-associated wildlife by establishing a diverse community of native vegetation in crested wheatgrass stands have largely failed. Instead of concentratin...

  13. INCREASING NATIVE PLANT DIVERSITY IN CRESTED WHEATGRASS STANDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crested wheatgrass was introduced to North America to improve degraded rangelands and has proven to be a successful revegetation species due to its ease of establishment, strong competitive ability, and grazing tolerance. However, crested wheatgrass may form monotypic stands with low plant diversit...

  14. FGF signaling transforms non-neural ectoderm into neural crest.

    PubMed

    Yardley, Nathan; García-Castro, Martín I

    2012-12-15

    The neural crest arises at the border between the neural plate and the adjacent non-neural ectoderm. It has been suggested that both neural and non-neural ectoderm can contribute to the neural crest. Several studies have examined the molecular mechanisms that regulate neural crest induction in neuralized tissues or the neural plate border. Here, using the chick as a model system, we address the molecular mechanisms by which non-neural ectoderm generates neural crest. We report that in response to FGF the non-neural ectoderm can ectopically express several early neural crest markers (Pax7, Msx1, Dlx5, Sox9, FoxD3, Snail2, and Sox10). Importantly this response to FGF signaling can occur without inducing ectopic mesodermal tissues. Furthermore, the non-neural ectoderm responds to FGF by expressing the prospective neural marker Sox3, but it does not express definitive markers of neural or anterior neural (Sox2 and Otx2) tissues. These results suggest that the non-neural ectoderm can launch the neural crest program in the absence of mesoderm, without acquiring definitive neural character. Finally, we report that prior to the upregulation of these neural crest markers, the non-neural ectoderm upregulates both BMP and Wnt molecules in response to FGF. Our results provide the first effort to understand the molecular events leading to neural crest development via the non-neural ectoderm in amniotes and present a distinct response to FGF signaling. PMID:23000357

  15. Vesicularity of basalt erupted at Reykjanes Ridge crest

    USGS Publications Warehouse

    Duffield, W.A.

    1978-01-01

    Average vesicularity of basalt drilled at three sites on the west flank of the Reykjanes Ridge increases with decreasing age. This change apparently records concomitant decrease in water depth at the ridge crest where the basalt was erupted and suggests substantial upward growth of the crest during the past 35 Myr. ?? 1978 Nature Publishing Group.

  16. A DNA mimic: the structure and mechanism of action for the anti-repressor protein AbbA.

    PubMed

    Tucker, Ashley T; Bobay, Benjamin G; Banse, Allison V; Olson, Andrew L; Soderblom, Erik J; Moseley, M Arthur; Thompson, Richele J; Varney, Kristen M; Losick, Richard; Cavanagh, John

    2014-05-01

    Bacteria respond to adverse environmental conditions by switching on the expression of large numbers of genes that enable them to adapt to unfavorable circumstances. In Bacillus subtilis, many adaptive genes are under the negative control of the global transition state regulator, the repressor protein AbrB. Stressful conditions lead to the de-repression of genes under AbrB control. Contributing to this de-repression is AbbA, an anti-repressor that binds to and blocks AbrB from binding to DNA. Here, we have determined the NMR structure of the functional AbbA dimer, confirmed that it binds to the N-terminal DNA-binding domain of AbrB, and have provided an initial description for the interaction using computational docking procedures. Interestingly, we show that AbbA has structural and surface characteristics that closely mimic the DNA phosphate backbone, enabling it to readily carry out its physiological function. PMID:24534728

  17. A DNA Mimic: The Structure and Mechanism of Action for the Anti-Repressor Protein AbbA

    PubMed Central

    Tucker, Ashley T.; Bobay, Benjamin G.; Banse, Allison V.; Olson, Andrew L.; Soderblom, Erik J.; Moseley, M. Arthur; Thompson, Richele J.; Varney, Kristen M.; Losick, Richard; Cavanagh, John

    2014-01-01

    Bacteria respond to adverse environmental conditions by switching on the expression of large numbers of genes that enable them to adapt to unfavorable circumstances. In Bacillus subtilis, many adaptive genes are under the negative control of the global transition state regulator, the repressor protein AbrB. Stressful conditions lead to the de-repression of genes under AbrB control. Contributing to this de-repression is AbbA, an anti-repressor that binds to and blocks AbrB from binding to DNA. Here, we have determined the NMR structure of the functional AbbA dimer, confirmed that it binds to the N-terminal DNA-binding domain of AbrB, and have provided an initial description for the interaction using computational docking procedures. Interestingly, we show that AbbA has structural and surface characteristics that closely mimic the DNA phosphate backbone, enabling it to readily carry out its physiological function. PMID:24534728

  18. What is the diffraction limit? From Airy to Abbe using direct numerical integration

    NASA Astrophysics Data System (ADS)

    Calm, Y. M.; Merlo, J. M.; Burns, M. J.; Kempa, K.; Naughton, M. J.

    The resolution of a conventional optical microscope is sometimes taken from Airy's point spread function (PSF), 0 . 61 λ / NA , and sometimes from Abbe, λ / 2 NA , where NA is the numerical aperture, however modern fluorescence and near-field optical microscopies achieve spatial resolution far better than either of these limits. There is a new category of 2D metamaterials called planar optical elements (POEs), which have a microscopic thickness (< λ), macroscopic transverse dimensions (> 100 λ), and are composed of an array of nanostructured light scatterers. POEs are found in a range of micro- and nano-photonic technologies, and will influence the future optical nanoscopy. With this pretext, we shed some light on the 'diffraction limit' by numerically evaluating Kirchhoff's scalar formulae (in their exact form) and identifying the features of highly non-paraxial, 3D PSFs. We show that the Airy and Abbe criteria are connected, and we comment on the design rules for a particular type of POE: the flat lens. This work is supported by the W. M. Keck Foundation.

  19. [Is Turkish bath water potable?: The baths of Sidi-Bel-Abbes].

    PubMed

    Benouis, K; Benabderrahmane, M; Harrache-Chettouh, Djamila; Benabdeli, K

    2008-01-01

    In Algeria, large numbers of people regularly go to Turkish baths or "Hammams". The cold tap water of the baths in the town of Sidi-Bel-Abbes (Algeria) comes either from wells or from a mixture of potable waterworks water and well water. Its principal use is for personal hygiene (washing). However, the steam heat generates thirst that can cause users to drink cold water during the steam bath. In addition, the wells feeding the baths are often poorly protected and especially badly treated. To ascertain whether their water quality, particularly bacteriological, meets the requirements for drinking water, we studied the characteristics of water from ten Turkish baths in Sidi-Bel-Abbes. Bacteriological analyses of cold water showed signs of contamination of fecal origin in 50% of the samples analysed. Moreover two water points from two of the baths appeared to have permanent fecal contamination. The physicochemical analysis showed that the water was very high in calcium (up to 550 mg/L) and magnesium (up to 299 mg/L). The maximum nitrate level observed was 68 mg/L. This study thus showed the existence of a health risk due to deterioration in the quality of the bath water and demonstrated the need for protection of the wells, frequent purification, and regular microbiological testing. PMID:19188127

  20. Correction of Abbe error in involute gear measurement using a laser interferometric system

    NASA Astrophysics Data System (ADS)

    Lin, Hu; Xue, Zi; Yang, Guoliang

    2015-10-01

    For correction of Abbe error in involute gear measurement, a laser interferometric measuring system is applied, in this system, the laser beam is split into two paths, one path is arranged tangent to the base circle of gear for measurement of profile, another path is arranged parallel to the gear axis for measurement of helix, two cube-corner reflectors are attached at the end of probe stylus closing to the tip, by this approach, the length offset between probe tip and reference scale is minimized , finally, the Abbe error is decreased. On another hand, the laser measuring error is caused by bending of stylus, the mathematic relationship between amount of bending and probe deflection is deduced. To determine the parameters in this mathematic relationship, two sizes of stylus are used for experiments. Experiments are carried out in a range of +/-0.8mm for probe deflection. Results show that the amount of stylus bending is linear with deflection of probe, the laser measuring error caused by stylus bending will be smaller than 0.3μm after correction.

  1. 78 FR 52974 - Gamesa Technology Corporation, Including On-Site Leased Workers From A & A Wind Pros Inc., ABB...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-27

    ...., Spherion ``The Mergis Group,'' System One, UpWind Solutions Inc., Wind Solutions LLC, and Wind Turbine... & A Wind Pros Inc., ABB Inc., Airway Services Inc., Amerisafe Consulting & Safety Services, Apex Alternative Access, Avanti Wind Systems, Inc., Broadwind Services LLC, Electric Power Systems...

  2. Crest line minimal model for sand dune

    NASA Astrophysics Data System (ADS)

    Guignier, Lucie; Valance, Alexandre; Lague, Dimitri

    2013-04-01

    In desert, complex patterns of dunes form. Under unidirectional wind, transverse rectilinear dunes or crescent shaped dunes called barchan dunes can appear, depending on the amount of sediment available. Most rectilinear transverse sand dunes are observed to fragment, for example at White Sands (New Mexico, United States of America) or Walvis Bay (Namibia). We develop a reduced complexity model to investigate the morphodynamics of sand dunes migrating over a non-erodible bed under unidirectional wind. The model is simply based on two physical ingredients, namely, the sand capture process at the slip face and the cross-wind sand transport. The efficiency of the sand capture process is taken to be dependent of the dune height and lateral diffusion is considered on both the windward and lee sides of the dune. In addition, the dune cross section is assumed to be scale invariant and is approximated by a triangular shape. In this framework, the dune dynamics is reduced to the motion of a string representing the dune crest line and is expressed as a set of two coupled nonlinear differential equations. This simple model reveals its ability to reproduce basic features of barchan and transverse dunes. Analytical predictions are drawn concerning dune equilibrium shape, stability and long-term dynamics. We derive, in particular, analytical solutions for barchan dunes, yielding explicit relationships between their shape and the lateral sand diffusion; and analytical predictions for the migration speed and equilibrium sand flux. A stability analysis of a rectilinear transverse dune allows us to predict analytically the wavelength emerging from fluctuations of the dune crest. We also determine the characteristic time needed for the rectilinear dune to fragment into a multitude of barchan dunes. These outcomes show that extremely simple ingredients can generate complex patterns for migrating dunes. From several dune field data, we are able to determine values of the model

  3. Worm drive detail, roller hoist mechanism, rolling crest roller gate ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Worm drive detail, roller hoist mechanism, rolling crest roller gate - plan and sections - Grand Valley Diversion Dam, Half a mile north of intersection of I-70 & Colorado State Route 65, Cameo, Mesa County, CO

  4. 31. AVALON DAM OUTLET WORKS FROM CREST OF DAM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. AVALON DAM - OUTLET WORKS FROM CREST OF DAM INCLUDING SPILLWAY NO. 1 AND CYLINDER GATE DISCHARGE PORTALS. VIEW TO SOUTHEAST - Carlsbad Irrigation District, Avalon Dam, On Pecos River, 4 miles North of Carlsbad, Carlsbad, Eddy County, NM

  5. 28. VIEW OF BRIDGE, LOOKING WEST FROM CREST OF HILL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. VIEW OF BRIDGE, LOOKING WEST FROM CREST OF HILL ABOVE EAST TOWER. NOTE SWAY CABLES ON EACH SIDE OF THE WALKWAY. March 1987 - Verde River Sheep Bridge, Spanning Verde River (Tonto National Forest), Cave Creek, Maricopa County, AZ

  6. 6. CREST ROAD ON UPPER EMBANKMENT, SHOWING MASONRY UPSTREAM PARAPET ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. CREST ROAD ON UPPER EMBANKMENT, SHOWING MASONRY UPSTREAM PARAPET WALL (LEFT) AND ENTRANCE TO DEER FLAT NAMPA CANAL HEADWORKS (ALSO LEFT). VIEW TO WEST. - Boise Project, Deer Flat Embankments, Lake Lowell, Nampa, Canyon County, ID

  7. 23. Detail, ridge cresting and finial elements, deteriorated slates, southeast ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. Detail, ridge cresting and finial elements, deteriorated slates, southeast roof slope, view to northwest from lift-bed truck, 135mm lens. - Southern Pacific Depot, 559 El Camino Real, San Carlos, San Mateo County, CA

  8. Central Retinal Enrichment Supplementation Trials (CREST): Design and Methodology of the CREST Randomized Controlled Trials

    PubMed Central

    Beatty, Stephen; Stack, Jim; Dennison, Jessica; O’Regan, Sarah; Meagher, Katherine A.; Peto, Tunde; Nolan, John

    2014-01-01

    Purpose The Central Retinal Enrichment Supplementation Trials (CREST) aim to investigate the potential impact of macular pigment (MP) enrichment, following supplementation with a formulation containing 10 mg lutein (L), 2 mg zeaxanthin (Z) and 10 mg meso-zeaxanthin (MZ), on visual function in normal subjects (Trial 1) and in subjects with early age-related macular degeneration (AMD; Trial 2). Methods CREST is a single center, double-blind, randomized clinical trial. Trial 1 (12-month follow-up) subjects are randomly assigned to a formulation containing 10 mg L, 10 mg MZ and 2 mg Z (n = 60) or placebo (n = 60). Trial 2 (24-month follow-up) subjects are randomly assigned to a formulation containing 10 mg L, 10 mg MZ, 2 mg Z plus 500 mg vitamin C, 400 IU vitamin E, 25 mg zinc and 2 mg copper (Intervention A; n = 75) or 10 mg L and 2 mg Z plus 500 mg vitamin C, 400 IU vitamin E, 25 mg zinc and 2 mg copper (Intervention B; n = 75). Contrast sensitivity (CS) at 6 cycles per degree represents the primary outcome measure in each trial. Secondary outcomes include: CS at other spatial frequencies, MP, best-corrected visual acuity, glare disability, photostress recovery, light scatter, cognitive function, foveal architecture, serum carotenoid concentrations, and subjective visual function. For Trial 2, AMD morphology, reading speed and reading acuity are also being recorded. Conclusions CREST is the first study to investigate the impact of supplementation with all three macular carotenoids in the context of a large, double-blind, randomized clinical trial. PMID:24621122

  9. Pentimento: Neural Crest and the origin of mesectoderm.

    PubMed

    Weston, James A; Thiery, Jean Paul

    2015-05-01

    The Neural Crest, a transient epithelium in vertebrate embryos, is the source of putative stem cells known to give rise to neuronal, glial and endocrine components of the peripheral (sensory, autonomic and enteric) nervous system (PNS) and pigment cells in the skin. The Neural Crest is also widely believed to be the source of mesectodermal derivatives (skeletogenic, odontogenic, connective tissue and smooth muscle mesenchyme) in the vertebrate head [see (Bronner and LeDouarin, 2012; Le Douarin, 2012; Le Douarin and Kalcheim, 1999); see also (Hörstadius, 1950; Weston, 1970)]. This conventional understanding of the broad developmental potential of the Neural Crest has been challenged over the past few years (Breau et al., 2008; Lee et al., 2013a, 2013b; Weston et al., 2004), based on recognition that the definition of the embryonic epithelia that comprise the Neural Crest may be imprecise. Indeed, the definition of the embryonic tissues understood to constitute the Neural Crest has changed considerably since it was first described by Wilhelm His 150 years ago (His, 1868). Today, the operational definition of the Neural Crest is inconsistent and functionally ambiguous. We believe that more precise definitions of the embryonic tissues involved in Neural Crest development would be useful to understand (1) the range of cellular phenotypes that actually segregate from it, (2) when this lineage diversification occurs, and (3) how diversification is regulated. In this idiosyncratic review, we aim to explain our concerns with the current definitions in this field, and in the chiastic words of Samuel Johnson (1781), "… make new things familiar and familiar things new".(1) Then, we will try to distinguish the developmental events crucial to the regulation of Neural Crest development at both cranial and trunk axial levels of vertebrate embryos, and address some of the implicit assumptions that underlie the conventional interpretation of experimental results on the origin and

  10. Flow structure in front of the broad-crested weir

    NASA Astrophysics Data System (ADS)

    Zachoval, Zbyněk; Roušar, Ladislav

    2015-05-01

    The paper deals with research focused on description of flow structure in front of broad-crested weir. Based on experimental measurement, the flow structure in front of the weir (the recirculation zone of flow and tornado vortices) and flow structure on the weir crest has been described. The determined flow character has been simulated using numerical model and based on comparing results the suitable model of turbulence has been recommended.

  11. Requirement for Foxd3 in Maintenance of Neural Crest Progenitors

    PubMed Central

    Teng, Lu; Mundell, Nathan A.; Frist, Audrey Y.; Wang, Qiaohong; Labosky, Patricia A.

    2008-01-01

    Summary Understanding the molecular mechanisms of stem cell maintenance is critical for the ultimate goal of manipulating stem cells for treatment of disease. Foxd3 is required early in mouse embryogenesis; Foxd3−/− embryos fail around the time of implantation, cells of the inner cell mass cannot be maintained in vitro, and blastocyst-derived stem cell lines cannot be established. Here, we report that Foxd3 is required for maintenance of the multipotent mammalian neural crest. Using tissue specific deletion of Foxd3 in the neural crest, we show that Foxd3flox/−; Wnt1-Cre mice die perinatally with a catastrophic loss of neural crest-derived structures. Cranial neural crest tissues are either missing or severely reduced in size, the peripheral nervous system consists of reduced dorsal root ganglia and cranial nerves, and the entire gastrointestinal tract is devoid of neural crest derivatives. These results demonstrate a global role for this transcriptional repressor in all aspects of neural crest maintenance along the anterior-posterior axis, and establish an unprecedented molecular link between multiple divergent progenitor lineages of the mammalian embryo. PMID:18367558

  12. CREST: Climate REconstruction SofTware

    NASA Astrophysics Data System (ADS)

    Chevalier, M.; Cheddadi, R.; Chase, B. M.

    2014-02-01

    Several methods currently exist to quantitatively reconstruct palaeoclimatic variables from fossil botanical data. Of these, pdf-based (probability density functions) methods have proven valuable as they can be applied to a wide range of plants assemblages. Most commonly applied to fossil pollen data, their performance, however, can be limited by the taxonomic resolution of the pollen data, as many species may belong to a given pollen-type. Consequently, the climate information associated with different species cannot sometimes not be precisely identified, resulting less accurate reconstructions. This can become particularly problematic in regions of high biodiversity. In this paper, we propose a novel pdf-based method that takes into account the different climatic requirements of each species constituting the broader pollen-type. Pdfs are fitted in two successive steps, with parametric pdfs fitted first for each species, and then a combination of those individual species pdfs into a broader single pdf to represent the pollen-type as a unit. A climate value for the pollen assemblage is estimated from the likelihood function obtained after the multiplication of the pollen-type pdfs, with each being weighted according to its pollen percentage. To test the robustness of the method, we have applied the method to southern Africa as a regional case study, and reconstructed a suite of climatic variables based on extensive botanical data derived from herbarium collections. The reconstructions proved to be accurate for both temperature and precipitation. Predictable exceptions were areas that experience conditions at the extremes of the regional climatic spectra. Importantly, the accuracy of the reconstructed values is independent from the vegetation type where the method is applied or the number of species used. The method used in this study is publicly available in a software package entitled CREST (Climate REconstruction SofTware) and will provide the opportunity to

  13. Serotonin regulates mouse cranial neural crest migration.

    PubMed Central

    Moiseiwitsch, J R; Lauder, J M

    1995-01-01

    Serotonergic agents (uptake inhibitors, receptor ligands) cause significant craniofacial malformations in cultured mouse embryos suggesting that 5-hydroxytryptamine (serotonin) (5-HT) may be an important regulator of craniofacial development. To determine whether serotonergic regulation of cell migration might underly some of these effects, cranial neural crest (NC) explants from embryonic day 9 (E9) (plug day = E1) mouse embryos or dissociated mandibular mesenchyme cells (derived from NC) from E12 embryos were placed in a modified Boyden chamber to measure effects of serotonergic agents on cell migration. A dose-dependent effect of 5-HT on the migration of highly motile cranial NC cells was demonstrated, such that low concentrations of 5-HT stimulated migration, whereas this effect was progressively lost as the dose of 5-HT was increased. In contrast, most concentrations of 5-HT inhibited migration of less motile, mandibular mesenchyme cells. To investigate the possible involvement of specific 5-HT receptors in the stimulation of NC migration, several 5-HT subtype-selective antagonists were used to block the effects of the most stimulatory dose of 5-HT (0.01 microM). Only NAN-190 (a 5-HT1A antagonist) inhibited the effect of 5-HT, suggesting involvement of this receptor. Further evidence was obtained by using immunohistochemistry with 5-HT receptor antibodies, which revealed expression of the 5-HT1A receptor but not other subtypes by migrating NC cells in both embryos and cranial NC explants. These results suggest that by activating appropriate receptors 5-HT may regulate migration of cranial NC cells and their mesenchymal derivatives in the mouse embryo. Images Fig. 1 Fig. 2 Fig. 3 PMID:7638165

  14. CREST--classification resources for environmental sequence tags.

    PubMed

    Lanzén, Anders; Jørgensen, Steffen L; Huson, Daniel H; Gorfer, Markus; Grindhaug, Svenn Helge; Jonassen, Inge; Øvreås, Lise; Urich, Tim

    2012-01-01

    Sequencing of taxonomic or phylogenetic markers is becoming a fast and efficient method for studying environmental microbial communities. This has resulted in a steadily growing collection of marker sequences, most notably of the small-subunit (SSU) ribosomal RNA gene, and an increased understanding of microbial phylogeny, diversity and community composition patterns. However, to utilize these large datasets together with new sequencing technologies, a reliable and flexible system for taxonomic classification is critical. We developed CREST (Classification Resources for Environmental Sequence Tags), a set of resources and tools for generating and utilizing custom taxonomies and reference datasets for classification of environmental sequences. CREST uses an alignment-based classification method with the lowest common ancestor algorithm. It also uses explicit rank similarity criteria to reduce false positives and identify novel taxa. We implemented this method in a web server, a command line tool and the graphical user interfaced program MEGAN. Further, we provide the SSU rRNA reference database and taxonomy SilvaMod, derived from the publicly available SILVA SSURef, for classification of sequences from bacteria, archaea and eukaryotes. Using cross-validation and environmental datasets, we compared the performance of CREST and SilvaMod to the RDP Classifier. We also utilized Greengenes as a reference database, both with CREST and the RDP Classifier. These analyses indicate that CREST performs better than alignment-free methods with higher recall rate (sensitivity) as well as precision, and with the ability to accurately identify most sequences from novel taxa. Classification using SilvaMod performed better than with Greengenes, particularly when applied to environmental sequences. CREST is freely available under a GNU General Public License (v3) from http://apps.cbu.uib.no/crest and http://lcaclassifier.googlecode.com. PMID:23145153

  15. Searching transients in large-scale surveys. A method based on the Abbe value

    NASA Astrophysics Data System (ADS)

    Mowlavi, N.

    2014-08-01

    Aims: A new method is presented to identify transient candidates in large-scale surveys based on the variability pattern in their light curves. Methods: The method is based on the Abbe value, Ab, that estimates the smoothness of a light curve, and on a newly introduced value called the excess Abbe and denoted excessAb, that estimates the regularity of the light curve variability pattern over the duration of the observations. Results: Based on simulated light curves, transients are shown to occupy a specific region in the {diagram} diagram, distinct from sources presenting pulsating-like features in their light curves or having featureless light curves. The method is tested on real light curves taken from EROS-2 and OGLE-II surveys in a 0.50° × 0.17° field of the sky in the Large Magellanic Cloud centered at RA(J2000) = 5h25m56.5s and Dec(J2000) = -69d29m43.3s. The method identifies 43 EROS-2 transient candidates out of a total of 1300 variable stars, and 19 more OGLE-II candidates, 10 of which do not have any EROS-2 variable star matches and which would need further confirmation to assess their reliability. The efficiency of the method is further tested by comparing the list of transient candidates with known Be stars in the literature. It is shown that all Be stars known in the studied field of view with detectable bursts or outbursts are successfully extracted by the method. In addition, four new transient candidates displaying bursts and/or outbursts are found in the field, of which at least two are good new Be candidates. Conclusions: The new method proves to be a potentially powerful tool to extract transient candidates from large-scale multi-epoch surveys. The better the photometric measurement uncertainties are, the cleaner the list of detected transient candidates is. In addition, the diagram diagram is shown to be a good diagnostic tool to check the data quality of multi-epoch photometric surveys. A trend of instrumental and/or data reduction origin

  16. Predictability of sacral base levelness based on iliac crest measurements.

    PubMed

    Dott, G A; Hart, C L; McKay, C

    1994-05-01

    A level sacral base plane is necessary to allow normalization of complex lumbosacral mechanics. Palpatory examinations are often used to evaluate for leg length discrepancy and pelvic obliquity despite improved accuracy and consistency of radiographic techniques. Treatment based on palpatory examinations suppose a direct and consistent relationship between the pelvic bones (innominates) and the sacral base. To evaluate the relationship between iliac crest levelness and sacral base levelness, a radiographic postural survey in the upright, weight-bearing position was performed on 358 men and women thought to have pelvic obliquity. Of these subjects, 293 demonstrated unlevel iliac crest heights or sacral base > or = 3/16 inch (4.76 mm), with iliac crest heights accurately predicting sacral base position 62% of the time. At > or = 3/8 inch (9.53 mm), 68% of the cases were accurately predicted. When the criterion for unlevelness was increased to > or = 1/2 inch (12.70 mm), the predictive accuracy improved to 83%. Radiographic findings in this study demonstrate a significant difference between iliac crest heights and sacral base position. In cases of mild to moderate short leg syndromes, the iliac crest height is an unreliable predictor of the direction or degree of sacral base levelness. PMID:8056627

  17. The Neural Crest and Cancer: A Developmental Spin on Melanoma

    PubMed Central

    Kulesa, Paul M.; Morrison, Jason A.; Bailey, Caleb M.

    2013-01-01

    Neural crest (NC) cells undergo an epithelial-to-mesenchymal transition (EMT) in order to exit from the dorsal neural tube. Similarly, ancestrally-related melanoma cells employ an EMT-like event during the initial stages of metastasis to dissociate from surrounding keratinocytes. Whether the molecular pathogenesis and cellular dynamics of melanoma metastasis resemble the embryonic NC invasion program is unclear. Here, we highlight advances in our understanding of tumor cell behaviors and plasticity, focusing on the relationship between melanoma and the neural crest invasion programs. We summarize recent discoveries of neural crest cell guidance and emerging in vivo imaging strategies that permit single cell resolution of fluorescently labeled tumor cells, with a focus on our recently developed in vivo chick embryo transplant model. Crucial to the molecular pathogenesis of metastasis, we highlight advances in gene profiling of small cell numbers, including our novel ability to gather gene expression information during distinct stages of melanoma invasion. Lastly, we present preliminary details of a comparison of specific genetic pathways associated with the early phases of melanoma invasion and known neural crest induction and migration signals. Our results suggest that malignant melanoma cells hijack portions of the neural crest program to promote plasticity and facilitate metastasis. In summary, there is considerable power in combining an in vivo model system with molecular analysis of gene expression, within the context of established developmental signaling pathways, to identify and study the molecular mechanisms of metastasis. PMID:23774755

  18. CONFIRMATORY SURVEY RESULTS FOR PORTIONS OF THE ABB COMBUSTION ENGINEERING SITE IN WINDSOR, CONNECTICUT DURING THE FALL OF 2011

    SciTech Connect

    Wade C. Adams

    2011-12-09

    From the mid-1950s until mid-2000, the Combustion Engineering, Inc. (CE) site in Windsor, Connecticut (Figure A-1) was involved in the research, development, engineering, production, and servicing of nuclear fuels, systems, and services. The site is currently undergoing decommissioning that will lead to license termination and unrestricted release in accordance with the requirements of the License Termination Rule in 10 CFR Part 20, Subpart E. Asea Brown Boveri Incorporated (ABB) has been decommissioning the CE site since 2001.

  19. "CONFIRMATORY SURVEY RESULTS FOR THE ABB COMBUSTION ENGINEERING SITE WINDSOR, CONNECTICUT DCN 5158-SR-02-2

    SciTech Connect

    ADAMS, WADE C

    2013-03-25

    The objectives of the confirmatory activities were to provide independent contractor field data reviews and to generate independent radiological data for use by the NRC in evaluating the adequacy and accuracy of the contractor's procedures and FSS results. ORAU reviewed ABB CE's decommissioning plan, final status survey plan, and the applicable soil DCGLs, which were developed based on an NRC-approved radiation dose assessment. The surveys include gamma surface scans, gamma direct measurements, and soil sampling.

  20. Large Break LOCA Safety Injection Sensitivity for a CE/ABB System 80+ PWR

    SciTech Connect

    Pottorf, J.; Bajorek, S.M.

    2002-07-01

    A WCOBRA/TRAC model of an evolutionary pressurized water reactor with direct vessel injection was constructed using publicly available information and a hypothetical double-ended guillotine break of a cold leg pipe was simulated. The model is an approximation of a ABB/Combustion Engineering System 80+ pressurized water reactor (PWR). WCOBRA/TRAC is the thermal-hydraulics code approved by the U.S. Nuclear Regulatory Commission for use in realistic large break LOCA analyses of Westinghouse 3- and 4-loop PWRs and the AP600 passive design. The AP600 design uses direct vessel injection, and the applicability of WCOBRA/TRAC to such designs is supported by comparisons to appropriate test data. This study extends the application of WCOBRA/TRAC to the investigation of the predicted behavior of direct vessel injection in an evolutionary design. A series of large break LOCA simulations were performed assuming a core power of 3914 MWt, and Technical Specification limits of 2.5 on total peaking factor and 1.7 on hot channel enthalpy rise factor. Two cladding temperature peaks were predicted during reflood, one following bottom of core recovery and a second caused by saturated boiling of water in the downcomer. This behavior is consistent with prior WCOBRA/TRAC calculations for some Westinghouse PWRs. The simulation results are described, and the sensitivity to failure assumptions for the safety injection system is presented. (authors)

  1. Drop Test Results for the Combustion Engineering Model No. ABB-2901 Fuel Pellet Package

    SciTech Connect

    Hafner, R S; Mok, G C; Hagler, L G

    2004-04-23

    The U.S. Nuclear Regulatory Commission (USNRC) contracted with the Packaging Review Group (PRG) at Lawrence Livermore National Laboratory (LLNL) to conduct a single, 30-ft shallow-angle drop test on the Combustion Engineering ABB-2901 drum-type shipping package. The purpose of the test was to determine if bolted-ring drum closures could fail during shallow-angle drops. The PRG at LLNL planned the test, and Defense Technologies Engineering Division (DTED) personnel from LLNL's Site-300 Test Group executed the plan. The test was conducted in November 2001 using the drop-tower facility at LLNL's Site 300. Two representatives from Westinghouse Electric Company in Columbia, South Carolina (WEC-SC); two USNRC staff members; and three PRG members from LLNL witnessed the preliminary test runs and the final test. The single test clearly demonstrated the vulnerability of the bolted-ring drum closure to shallow-angle drops-the test package's drum closure was easily and totally separated from the drum package. The results of the preliminary test runs and the 30-ft shallow-angle drop test offer valuable qualitative understandings of the shallow-angle impact.

  2. Piping benchmark problems for the ABB/CE System 80+ Standardized Plant

    SciTech Connect

    Bezler, P.; DeGrassi, G.; Braverman, J.; Wang, Y.K.

    1994-07-01

    To satisfy the need for verification of the computer programs and modeling techniques that will be used to perform the final piping analyses for the ABB/Combustion Engineering System 80+ Standardized Plant, three benchmark problems were developed. The problems are representative piping systems subjected to representative dynamic loads with solutions developed using the methods being proposed for analysis for the System 80+ standard design. It will be required that the combined license licensees demonstrate that their solution to these problems are in agreement with the benchmark problem set. The first System 80+ piping benchmark is a uniform support motion response spectrum solution for one section of the feedwater piping subjected to safe shutdown seismic loads. The second System 80+ piping benchmark is a time history solution for the feedwater piping subjected to the transient loading induced by a water hammer. The third System 80+ piping benchmark is a time history solution of the pressurizer surge line subjected to the accelerations induced by a main steam line pipe break. The System 80+ reactor is an advanced PWR type.

  3. Role of morphogens in neural crest cell determination.

    PubMed

    Jones, Natalie C; Trainor, Paul A

    2005-09-15

    The neural crest is a transient, migratory cell population found in all vertebrate embryos that generate a diverse range of cell and tissue derivatives including, but not limited, to the neurons and glia of the peripheral nervous system, smooth muscle, connective tissue, melanocytes, craniofacial cartilage, and bone. Over the past few years, many studies have provided tremendous insights into understanding the mechanisms regulating the induction and migration of neural crest cell development. This review highlights the surprising and perhaps unexpected roles for morphogens in these distinct processes. A comparison of studies performed in several different vertebrates emphasizes the requirement for coordination between multiple signaling pathways in the induction and migration of neural crest cells in the developing embryo. PMID:16041760

  4. Iliac Crest Avulsion Fracture in a Young Sprinter

    PubMed Central

    Casabianca, L.; Rousseau, R.; Loriaut, P.; Massein, A.; Mirouse, G.; Gerometta, A.; Khiami, F.

    2015-01-01

    Avulsion fracture of the iliac crest is an uncommon pathology. It usually occurs in teenagers during sport activities, more common in boys. We report a case of 16-year-old male competitive sprinter, who had an avulsion of a part of the iliac crest and the anterior-superior iliac spine during a competition. The traumatism occurred during the period of acceleration phase out of the blocks which corresponds to the maximum traction phase on the tendons. Then a total loss of function of the lower limb appears forcing him to stop the run. X-ray and CT scan confirmed the rare diagnosis of avulsion of the quasitotality of the iliac crest apophysis, corresponding to Salter 2 fracture. We performed an open reduction and internal fixation with two screws, allowing a return to sport after 3 months and his personal best record in the 100 meters at the 6th postoperative month. PMID:26421205

  5. CREST - a large and diverse superfamily of putative transmembrane hydrolases

    PubMed Central

    2011-01-01

    Background A number of membrane-spanning proteins possess enzymatic activity and catalyze important reactions involving proteins, lipids or other substrates located within or near lipid bilayers. Alkaline ceramidases are seven-transmembrane proteins that hydrolyze the amide bond in ceramide to form sphingosine. Recently, a group of putative transmembrane receptors called progestin and adipoQ receptors (PAQRs) were found to be distantly related to alkaline ceramidases, raising the possibility that they may also function as membrane enzymes. Results Using sensitive similarity search methods, we identified statistically significant sequence similarities among several transmembrane protein families including alkaline ceramidases and PAQRs. They were unified into a large and diverse superfamily of putative membrane-bound hydrolases called CREST (alkaline ceramidase, PAQR receptor, Per1, SID-1 and TMEM8). The CREST superfamily embraces a plethora of cellular functions and biochemical activities, including putative lipid-modifying enzymes such as ceramidases and the Per1 family of putative phospholipases involved in lipid remodeling of GPI-anchored proteins, putative hormone receptors, bacterial hemolysins, the TMEM8 family of putative tumor suppressors, and the SID-1 family of putative double-stranded RNA transporters involved in RNA interference. Extensive similarity searches and clustering analysis also revealed several groups of proteins with unknown function in the CREST superfamily. Members of the CREST superfamily share seven predicted core transmembrane segments with several conserved sequence motifs. Conclusions Universal conservation of a set of histidine and aspartate residues across all groups in the CREST superfamily, coupled with independent discoveries of hydrolase activities in alkaline ceramidases and the Per1 family as well as results from previous mutational studies of Per1, suggests that the majority of CREST members are metal-dependent hydrolases

  6. Negative chemotaxis does not control quail neural crest cell dispersion.

    PubMed

    Erickson, C A; Olivier, K R

    1983-04-01

    Negative chemotaxis has been proposed to direct dispersion of amphibian neural crest cells away from the neural tube (V. C. Twitty, 1949, Growth 13(Suppl. 9), 133-161). We have reexamined this hypothesis using quail neural crest and do not find evidence for it. When pigmented or freshly isolated neural crest cells are covered by glass shards to prevent diffusion of a "putative" chemotactic agent away from the cells and into the medium, we find a decrease in density of cells beneath the coverslip as did Twitty and Niu (1948, J. Exp. Zool. 108, 405-437). Unlike those investigators, however, we find the covered cells move slower than uncovered cells and that the decrease in density can be attributed to cessation of cell division and increased cell death in older cultures, rather than directed migration away from each other. In cell systems where negative chemotaxis has been demonstrated, a "no man's land" forms between two confronted explants (Oldfield, 1963, Exp. Cell Res. 30, 125-138). No such cell-free space forms between confronted neural crest explants, even if the explants are closely covered to prevent diffusion of the negative chemotactic material. If crest cell aggregates are drawn into capillary tubes to allow accumulation of the putative material, the cells disperse farther, the wider the capillary tube bore. This is contrary to what would be expected if dispersion depended on accumulation of this material. Also, no difference in dispersion is noted between cells in the center of the tubes versus cells near the mouth of the tubes where the tube medium is freely exchanging with external fresh medium. Alternative hypotheses for directionality of crest migration in vivo are discussed. PMID:6832483

  7. DEGRADATION OF EMISSIONS CONTROL PERFORMANCE OF WOODSTOVES IN CRESTED BUTTE, CO

    EPA Science Inventory

    The report discusses the degradation of emissions control performance of woodstoves in Crested Butte, Colorado. Four seasons of field monitoring of EPA-certified woodstoves in and around Crested Butte has demonstrated some significant failures in emissions control performance. In...

  8. Aebp2 as an epigenetic regulator for neural crest cells.

    PubMed

    Kim, Hana; Kang, Keunsoo; Ekram, Muhammad B; Roh, Tae-Young; Kim, Joomyeong

    2011-01-01

    Aebp2 is a potential targeting protein for the mammalian Polycomb Repression Complex 2 (PRC2). We generated a mutant mouse line disrupting the transcription of Aebp2 to investigate its in vivo roles. Aebp2-mutant homozygotes were embryonic lethal while heterozygotes survived to adulthood with fertility. In developing mouse embryos, Aebp2 is expressed mainly within cells of neural crest origin. In addition, many heterozygotes display a set of phenotypes, enlarged colon and hypopigmentation, similar to those observed in human patients with Hirschsprung's disease and Waardenburg syndrome. These phenotypes are usually caused by the absence of the neural crest-derived ganglia in hindguts and melanocytes. ChIP analyses demonstrated that the majority of the genes involved in the migration and development process of neural crest cells are downstream target genes of AEBP2 and PRC2. Furthermore, expression analyses confirmed that some of these genes are indeed affected in the Aebp2 heterozygotes. Taken together, these results suggest that Aebp2 may regulate the migration and development of the neural crest cells through the PRC2-mediated epigenetic mechanism. PMID:21949878

  9. Competitive Dynamics Among Crested Wheatgrass and Native Forbs and Grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extensive monocultures of exotic crested wheatgrass (Agropyron spp.) in the interior western United States replaced former wildlife habitat and in many cases are susceptible to or currently invaded by exotic annual grasses and forbs. Approaches are being examined for adding native species to improve...

  10. Restoring the sagebrush component in crested wheatgrass dominated communities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Monotypic stands of crested wheatgrass (Agropyron cristatum [L] Gaertm. and Agropyron desertorum [Fisch.] Schult.), an introduced grass, occupy vast expanses of the sagebrush steppe. Efforts to improve habitat for sagebrush-associated wildlife by establishing a diverse community of native vegetatio...

  11. Increased Seedling Vigor in 'Hycrest II' Crested Wheatgrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    "Hycrest II' crested wheatgrass (Agropyron cristatum L.) (Reg. No. CV-__, PI______). It has been estimated that cheatgrass (Bromus tectorum L.) has displaced around 10 million ha of perennial vegetation within the Great Basin. The control of cheatgrass without replacement by desirable perennial sp...

  12. AERIAL VIEW, LOOKING NORTHWEST TOWARDS JONES VALLEY FROM THE CREST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AERIAL VIEW, LOOKING NORTHWEST TOWARDS JONES VALLEY FROM THE CREST OF RED (CALLED RUFFNER) MOUNTAIN AND THE CITY OF BIRMINGHAM (TOP), WITH ABANDONED SLOSS CO. LIMESTONE QUARRIES (CENTER) AND RIGHT-OF-WAY OF THE L. & N. BIRMINGHAM MINERAL RAILROAD (LEFT CENTER TO BOTTOM RIGHT). - Ruffner Red Ore Mine, North of I-20 at Madrid Exit, Birmingham, Jefferson County, AL

  13. Oblique view, looking south of the concrete crest and apron ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Oblique view, looking south of the concrete crest and apron after dewatering of north side. The east abutment wall, is at left. Easternmost roller gate (raised position) and service bridge at top - Grand Valley Diversion Dam, Half a mile north of intersection of I-70 & Colorado State Route 65, Cameo, Mesa County, CO

  14. History of Crested Wheatgrass (Agropyron) in North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crested wheatgrass is indigenous to the Steppe region of European Russia and southwestern Siberia. It was first introduced into North America in 1892, by N. E. Hansen of the South Dakota Experiment Station. Dr. Hansen obtained five accessions, designated Pls 835, 837, 838, 1010, and 1012, from Val...

  15. LOOKING DOWNSTREAM FROM KACHESS DAM CREST, 1910 RIVER CUTOFF CHANNEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LOOKING DOWNSTREAM FROM KACHESS DAM CREST, 1910 RIVER CUTOFF CHANNEL WITH CRIB STRUCTURE IN CENTER. BRIDGE FOOTING CRIB STRUCTURE AT RIGHT (Upstream face of Kachess Dam in foreground) - Kachess Dam, Cutoff Channel and Crib Structures, Kachess River, 1.5 miles north of Interstate 90, Easton, Kittitas County, WA

  16. 6. VIEW SHOWING CREST OF DAM AND OUTLET GATE WHEEL, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW SHOWING CREST OF DAM AND OUTLET GATE WHEEL, STEM AND STEM GUIDE, LOOKING SOUTHEAST - High Mountain Dams in Upalco Unit, Milk Lake Dam, Ashley National Forest, 9.4 miles Northwest of Swift Creek Campground, Mountain Home, Duchesne County, UT

  17. 3. Side view of lower dam showing crest, overspill and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Side view of lower dam showing crest, overspill and apron. Photograph taken from west side of Millstone Creek. VIEW NORTHEAST - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

  18. 4. Side view of lower dam showing crest, overspill and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. Side view of lower dam showing crest, overspill and apron. Photograph taken from east side of Millstone Creek. VIEW SOUTHWEST - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

  19. 5. Rear view of lower dam showing crest, masonry pier ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Rear view of lower dam showing crest, masonry pier and sluice gate. Photograph taken from east bank of the sandy beach. VIEW SOUTH - Loleta Recreation Area, Lower Dam, 6 miles Southeast of interesection of State Route 24041 & State Route 66, Loleta, Elk County, PA

  20. Current perspectives of the signaling pathways directing neural crest induction.

    PubMed

    Stuhlmiller, Timothy J; García-Castro, Martín I

    2012-11-01

    The neural crest is a migratory population of embryonic cells with a tremendous potential to differentiate and contribute to nearly every organ system in the adult body. Over the past two decades, an incredible amount of research has given us a reasonable understanding of how these cells are generated. Neural crest induction involves the combinatorial input of multiple signaling pathways and transcription factors, and is thought to occur in two phases from gastrulation to neurulation. In the first phase, FGF and Wnt signaling induce NC progenitors at the border of the neural plate, activating the expression of members of the Msx, Pax, and Zic families, among others. In the second phase, BMP, Wnt, and Notch signaling maintain these progenitors and bring about the expression of definitive NC markers including Snail2, FoxD3, and Sox9/10. In recent years, additional signaling molecules and modulators of these pathways have been uncovered, creating an increasingly complex regulatory network. In this work, we provide a comprehensive review of the major signaling pathways that participate in neural crest induction, with a focus on recent developments and current perspectives. We provide a simplified model of early neural crest development and stress similarities and differences between four major model organisms: Xenopus, chick, zebrafish, and mouse. PMID:22547091

  1. 3. CREST OF THE SOUTH CHANNEL DAM, SHOWING BLOCK HOUSE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. CREST OF THE SOUTH CHANNEL DAM, SHOWING BLOCK HOUSE (NOT ORIGINAL) COVERING THE ELECTRICALLY POWERED GATE-LIFTING MECHANISM THAT REPLACED THE ORIGINAL HAND-OPERATED LIFTING DEVICE, LOOKING NORTH. - Washington Water Power Company Post Falls Power Plant, South Channel Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  2. In vitro clonal analysis of mouse neural crest development.

    PubMed

    Ito, K; Morita, T; Sieber-Blum, M

    1993-06-01

    Analysis of lineage segregation during mammalian neural crest development has not been sufficiently performed due to technical difficulties. In the present study, therefore, we established a clonal culture system of mouse neural crest cells in order to analyze developmental potentials of individual neural crest cells and their patterns of lineage segregation. 12-O-Tetradecanoylphorbol-13-acetate (TPA) and cholera toxin (CT) were applied to culture medium to trigger melanogenic differentiation of mouse neural crest cells. Three morphologically distinct types of clones were observed. (1) "Pigmented clones" consisted of melanocytes only, suggesting that the clone-forming cells were committed to the melanogenic lineage. These clones were observed only in the presence of TPA and CT. The proportion of this type of clone (8%) was much lower than that of the equivalent type of clone in quail trunk neural crest (40-60%; Sieber-Blum and Cohen, 1980, Dev. Biol. 80, 96-106). It therefore appears that the segregation pattern to the melanogenic lineage during mouse neural crest development in vitro differs quantitatively from that in the quail. (2) "Mixed clones" consisted of pigmented and unpigmented cells. Like pigmented clones, they were observed only in the presence of TPA and CT. The clones contained up to four types of cells: melanocytes, S100-positive cells (Schwann cells or melanogenic precursor cells), serotonin (5-HT)-positive autonomic neuron-like cells, and substance P (SP)-immunoreactive sensory neuron-like cells. Thus, at least some mixed clone-forming cells are pluripotent. (3) Two classes of "unpigmented clones" were observed that consisted of unpigmented cells only. These clones developed in the presence and absence of TPA and CT. Unpigmented clones in one class contained up to three types of cells as well as other, as yet unidentified cells: S100-, 5-HT-, and SP-positive cells. This observation suggests that at least some of these clones originate from cells

  3. 77 FR 40374 - Proposed Information Collection; Depredation Orders for Double-Crested Cormorants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-09

    ... Fish and Wildlife Service Proposed Information Collection; Depredation Orders for Double- Crested... Services) in 13 States to take double-crested cormorants when the birds are found committing or about to... federally recognized tribes in 24 States to take double-crested cormorants to prevent depredations on...

  4. Using CREST to Model Floods for the Upper Missouri Basin

    NASA Astrophysics Data System (ADS)

    Rodriguez, L.; Spelman, D.; Skym, P.; Oguamanam, M.

    2012-12-01

    The Upper Missouri River basin in Montana is prone to frequent floods during the months of May through June. During the summer of 2011, the duration of heavy rain and high snow melt caused floods in the Missouri Watershed to last for several weeks. Although organizations and citizens are aware of the flooding, the severity of any given flood is difficult to predict. Thus, a flood forecasting system would benefit the community by providing advance notice of areas prone to floods. The team addressed these issues by calibrating a fully distributed hydrological model on this region using the University of Oklahoma's Coupled Routing Excess STorage (CREST) 2.0 model. The CREST model contains ten internal parameters that must be optimized through calibration to in-situ data which was done using only remotely sensed data as inputs; these include: rainfall from TRMM, Digital Elevation Model (DEM) from SRTM, and potential evapotranspiration (PET). At a one kilometer spatial and three hour temporal resolutions, CREST was calibrated over a three year period. This calibration was unsuccessful, resulting in a maximum NSCE of just 0.24, due to the heavy impact of snow-pack melt on the hydrology of the Upper Missouri River watershed and the lack of snow melt inputs to the model. Because of this, a modeled snow melt product, which was selected to be the Snow Data Assimilation System (SNODAS), was implemented into the model for the first time. This implementation required substantial data processing prior to input as well as substantial troubleshooting within the CREST model. Additionally, the San Bernard watershed, which is in the absence of snow, was used and calibrated in the model for comparison. The arrangement of these calibrations was performed, and the necessary steps required were documented. However, the actual calibrations were not carried out due to lack of access needed in computational power and time. Significant progress was made in understanding the fundamental steps

  5. Comparative analysis of neural crest cell death, migration, and function during vertebrate embryogenesis.

    PubMed

    Kulesa, Paul; Ellies, Debra L; Trainor, Paul A

    2004-01-01

    Cranial neural crest cells are a multipotent, migratory population that generates most of the cartilage, bone, connective tissue and peripheral nervous system in the vertebrate head. Proper neural crest cell patterning is essential for normal craniofacial morphogenesis and is highly conserved among vertebrates. Neural crest cell patterning is intimately connected to the early segmentation of the neural tube, such that neural crest cells migrate in discrete segregated streams. Recent advances in live embryo imaging have begun to reveal the complex behaviour of neural crest cells which involve intricate cell-cell and cell-environment interactions. Despite the overall similarity in neural crest cell migration between distinct vertebrates species there are important mechanistic differences. Apoptosis for example, is important for neural crest cell patterning in chick embryos but not in mouse, frog or fish embryos. In this paper we highlight the potential evolutionary significance of such interspecies differences in jaw development and evolution. Developmental Dynamics 229:14-29, 2004. PMID:14699574

  6. Retinoic acid-binding protein, rhombomeres and the neural crest.

    PubMed

    Maden, M; Hunt, P; Eriksson, U; Kuroiwa, A; Krumlauf, R; Summerbell, D

    1991-01-01

    We have investigated by immunocytochemistry the spatial and temporal distribution of cellular retinoic acid-binding protein (CRABP) in the developing nervous system of the chick embryo in order to answer two specific questions: do neural crest cells contain CRABP and where and when do CRABP-positive neuroblasts first arise in the neural tube? With regard to the neural crest, we have compared CRABP staining with HNK-1 staining (a marker of migrating neural crest) and found that they do indeed co-localise, but cephalic and trunk crest behave slightly differently. In the cephalic region in tissues such as the frontonasal mass and branchial arches, HNK-1 immunoreactivity is intense at early stages, but it disappears as CRABP immunoreactivity appears. Thus the two staining patterns do not overlap, but are complementary. In the trunk, HNK-1 and CRABP stain the same cell populations at the same time, such as those migrating through the anterior halves of the somites. In the neural tube, CRABP-positive neuroblasts first appear in the rhombencephalon just after the neural folds close and then a particular pattern of immunoreactivity appears within the rhombomeres of the hindbrain. Labelled cells are present in the future spinal cord, the posterior rhombencephalon up to rhombomere 6 and in rhombomere 4 thus producing a single stripe pattern. This pattern is dynamic and gradually changes as anterior rhombomeres begin to label. The similarity of this initial pattern to the arrangement of certain homeobox genes in the mouse stimulated us to examine the expression of the chicken Hox-2.9 gene. We show that at stage 15 the pattern of expression of this gene is closely related to that of CRABP. The relationship between retinoic acid, CRABP and homeobox genes is discussed. PMID:1707786

  7. Environmental correlates of breeding in the Crested Caracara (Caracara Cheriway)

    USGS Publications Warehouse

    Morrison, J.L.; Pias, Kyle E.; Cohen, J.B.; Catlin, D.H.

    2009-01-01

    We evaluated the influence of weather on reproduction of the Crested Caracara (Caracara cheriway) in an agricultural landscape in south-central Florida. We used a mixed logistic-regression modeling approach within an information-theoretic framework to examine the influence of total rainfall, rainfall frequency, and temperature on the number of breeding pairs, timing of breeding, nest success, and productivity of Crested Caracaras during 1994-2000. The best models indicated an influence of rainfall frequency and laying period on reproduction. More individuals nested and more pairs nested earlier during years with more frequent rainfall in late summer and early fall. Pairs that nested later in each breeding season had smaller clutches, lower nest success and productivity, and higher probability of nest failure. More frequent rainfall during early spring months that are usually characterized by water deficit (March-May), more frequent rainfall during the fall drawdown period (September-November), and a shorter winter dry period showed some association with higher probability of brood reduction and lower nest success. The proportion of nests that failed was higher in "wet" years, when total rainfall during the breeding season (September-April) was >10% above the 20-year average. Rainfall may influence reproduction in Crested Caracaras indirectly through food resources. As total rainfall increased during February-April, when most pairs are feeding nestlings or dependent fledglings, the proportion of drawdown-dependent species (those that become available as rainfall decreases and wetlands become isolated and shallow) in the diet of Crested Caracaras declined, which may indicate reduced availability of foraging habitat for this primarily terrestrial raptor. ?? The American Ornithologists' Union, 2009.

  8. Chicken trunk neural crest migration visualized with HNK1

    PubMed Central

    Giovannone, Dion; Ortega, Blanca; Reyes, Michelle; El-Ghali, Nancy; Rabadi, Maes; Sao, Sothy; de Bellard, Maria Elena

    2015-01-01

    The development of the nervous system involves cells remaining within the neural tube (CNS) and a group of cells that delaminate from the dorsal neural tube and migrate extensively throughout the developing embryo called neural crest cells (NCC). These cells are a mesenchymal highly migratory group of cells that give rise to a wide variety of cell derivatives: melanocytes, sensory neurons, bone, Schwann cells, etc. But not all NCC can give rise to all derivatives, they have fate restrictions based on their axial level of origin: cranial, vagal, trunk and sacral. Our aim was to provide a thorough presentation on how does trunk neural crest cell migration looks in the chicken embryo, in wholemount and in sections using the unique chicken marker HNK1. The description presented here makes a good guideline for those interested in viewing trunk NCC migration patterns. We show how before HH14 there are few trunk NCC delaminating and migrating, but between HH15 through HH19 trunk NCC delaminate in large numbers. Melanocytes precursors begin to enter the dorsolateral pathway by HH17. We found that by HH20 HNK1 is not a valid good marker for NCC and that HNK1 is a better marker than Sox10 when looking at neural crest cells morphology and migration details. PMID:25805416

  9. Cranial Neural Crest Migration: New Rules for an Old Road

    PubMed Central

    Kulesa, Paul M.; Bailey, Caleb M.; Kasemeier-Kulesa, Jennifer C.; McLennan, Rebecca

    2010-01-01

    The neural crest serve as an excellent model to better understand mechanisms of embryonic cell migration. Cell tracing studies have shown that cranial neural crest cells (CNCCs) emerge from the dorsal neural tube in a rostrocaudal manner and are spatially distributed along stereotypical, long distance migratory routes to precise targets in the head and branchial arches. Although the CNCC migratory pattern is a beautifully choreographed and programmed invasion, the underlying orchestration of molecular events is not well known. For example, it is still unclear how single CNCCs react to signals that direct their choice of direction and how groups of CNCCs coordinate their interactions to arrive at a target in an ordered manner. In this review, we discuss recent cellular and molecular discoveries of the CNCC migratory pattern. We focus on events from the time when CNCCs encounter the tissue adjacent to the neural tube and their travel through different microenvironments and into the branchial arches. We describe the patterning of discrete cell migratory streams that emerge from the hindbrain, rhombomere (r) segments r1–r7, and the signals that coordinate directed migration. We propose a model that attempts to unify many complex events that establish the CNCC migratory pattern, and based on this model we integrate information between cranial and trunk neural crest development. PMID:20399765

  10. Regeneration of neural crest derivatives in the Xenopus tadpole tail

    PubMed Central

    Lin, Gufa; Chen, Ying; Slack, Jonathan MW

    2007-01-01

    Background After amputation of the Xenopus tadpole tail, a functionally competent new tail is regenerated. It contains spinal cord, notochord and muscle, each of which has previously been shown to derive from the corresponding tissue in the stump. The regeneration of the neural crest derivatives has not previously been examined and is described in this paper. Results Labelling of the spinal cord by electroporation, or by orthotopic grafting of transgenic tissue expressing GFP, shows that no cells emigrate from the spinal cord in the course of regeneration. There is very limited regeneration of the spinal ganglia, but new neurons as well as fibre tracts do appear in the regenerated spinal cord and the regenerated tail also contains abundant peripheral innervation. The regenerated tail contains a normal density of melanophores. Cell labelling experiments show that melanophores do not arise from the spinal cord during regeneration, nor from the mesenchymal tissues of the skin, but they do arise by activation and proliferation of pre-existing melanophore precursors. If tails are prepared lacking melanophores, then the regenerates also lack them. Conclusion On regeneration there is no induction of a new neural crest similar to that seen in embryonic development. However there is some regeneration of neural crest derivatives. Abundant melanophores are regenerated from unpigmented precursors, and, although spinal ganglia are not regenerated, sufficient sensory systems are produced to enable essential functions to continue. PMID:17521450

  11. Neural crest induction by paraxial mesoderm in Xenopus embryos requires FGF signals.

    PubMed

    Monsoro-Burq, Anne-Hélène; Fletcher, Russell B; Harland, Richard M

    2003-07-01

    At the border of the neural plate, the induction of the neural crest can be achieved by interactions with the epidermis, or with the underlying mesoderm. Wnt signals are required for the inducing activity of the epidermis in chick and amphibian embryos. Here, we analyze the molecular mechanisms of neural crest induction by the mesoderm in Xenopus embryos. Using a recombination assay, we show that prospective paraxial mesoderm induces a panel of neural crest markers (Slug, FoxD3, Zic5 and Sox9), whereas the future axial mesoderm only induces a subset of these genes. This induction is blocked by a dominant negative (dn) form of FGFR1. However, neither dnFGFR4a nor inhibition of Wnt signaling prevents neural crest induction in this system. Among the FGFs, FGF8 is strongly expressed by the paraxial mesoderm. FGF8 is sufficient to induce the neural crest markers FoxD3, Sox9 and Zic5 transiently in the animal cap assay. In vivo, FGF8 injections also expand the Slug expression domain. This suggests that FGF8 can initiate neural crest formation and cooperates with other DLMZ-derived factors to maintain and complete neural crest induction. In contrast to Wnts, eFGF or bFGF, FGF8 elicits neural crest induction in the absence of mesoderm induction and without a requirement for BMP antagonists. In vivo, it is difficult to dissociate the roles of FGF and WNT factors in mesoderm induction and neural patterning. We show that, in most cases, effects on neural crest formation were parallel to altered mesoderm or neural development. However, neural and neural crest patterning can be dissociated experimentally using different dominant-negative manipulations: while Nfz8 blocks both posterior neural plate formation and neural crest formation, dnFGFR4a blocks neural patterning without blocking neural crest formation. These results suggest that different signal transduction mechanisms may be used in neural crest induction, and anteroposterior neural patterning. PMID:12783784

  12. Discovery of transcription factors and other candidate regulators of neural crest development

    PubMed Central

    Adams, MS; Gammill, LS; Bronner-Fraser, M

    2011-01-01

    Neural crest cells migrate long distances and form divergent derivatives in vertebrate embryos. Despite previous efforts to identify genes upregulated in neural crest populations, transcription factors have proved to be elusive due to relatively low expression levels and often transient expression. We screened newly induced neural crest cells for early target genes with the aim of identifying transcriptional regulators and other developmentally important genes. This yielded numerous candidate regulators, including fourteen transcription factors, many of which were not previously associated with neural crest development. Quantitative real-time PCR confirmed upregulation of several transcription factors in newly induced neural crest populations in vitro. In a secondary screen by in situ hybridization, we verified the expression of >100 genes in the neural crest. We note that several of the transcription factors and other genes from the screen are expressed in other migratory cell populations and have been implicated in diverse forms of cancer. PMID:18351660

  13. Neural crest development in the Xenopus laevis embryo, studied by interspecific transplantation and scanning electron microscopy.

    PubMed

    Sadaghiani, B; Thiébaud, C H

    1987-11-01

    The Xenopus borealis quinacrine marker and scanning electron microscopy have been used to study the appearance, migration, and homing of neural crest cells in the embryo of Xenopus. The analysis shows that the primordium of the neural crest develops from the nervous layer of the ectoderm and consists of three segments at early neurula stages. This primordium is located in the lateral halves of the neural folds behind the prospective eye vesicles. The histological and experimental evidence shows that the neural crest cells also originate from the medial portion of the neural folds. The neural crest segments in the cephalic region start to migrate just before the closure of the neural tube. Isotopic and isochronic unilateral grafts of X. borealis neural crest into X. laevis embryos were performed in order to map the fate of the cranial crest segments and the vagal-truncal neural crest. The analysis of the X. laevis host embryos shows that the mandibular crest segment contributes to the lower jaw (Meckel's cartilage), quadrate, and ethmoid-trabecular cartilages, as well as to the ganglionic and Schwann cells of the trigeminus nerve, the connective tissues, the mesenchymal and choroid layers of the eye, and the cornea. The hyoid crest segment is located in the ceratohyal cartilage and in ganglia VII and VIII. The branchial crest segment migrates from the caudal part of the otic vesicle and divides into two portions which contribute to the cartilages of the gills. The vagal-truncal neural crest starts to migrate later at stage 25. It migrates by means of the vagus complex in a ventral direction and penetrates into the splanchnic layer of the digestive tract. The trunk neural crest cells disperse into three different pathways which differ from those of the avian embryo at this level. PMID:3666314

  14. Neural crest and placode contributions to olfactory development.

    PubMed

    Suzuki, Jun; Osumi, Noriko

    2015-01-01

    Olfaction is the sense of smell that influences many primitive behaviors for survival, e.g., feeding, reproduction, social interaction, and fear response. The olfactory system is an evolutionarily ancient sensory system and composed of the olfactory epithelium (OE), the olfactory bulb (OB), and the olfactory cortex. The OE gives rise to olfactory receptor neurons (ORNs), i.e., primary sensory receptor cells whose axons project directly to the OB. The ORNs are unique in the way that they are continuously replaced during physiological turnover or following injury throughout life. In the OE, horizontal basal cells, i.e., flat and quiescent cells attached to the basal lamina, are now thought to be tissue stem cells. Although OE cells, especially ORNs, were hypothesized to be derived from the olfactory placode (OP), recent genetic fate-mapping studies using Cre reporter mice indicate a dual origin, i.e., the OP and neural crest (NC), of the olfactory system. The NC is a transient embryonic tissue that is formed between the dorsal neuroepithelium and epidermis. Neural crest cells (NCCs) are multipotent cells that migrate into various target tissues and differentiate into various cell types, including neurons and glia of the peripheral nervous system, cranial cartilage and bone, and melanocytes. Recent studies have revealed that neural crest-derived cells (NCDCs) are widely distributed in adult tissues, and that a subset of NCDCs still possesses NCC-like multipotency. Here, we review classical and recent studies of the olfactory system, especially focusing on the contribution of the NC and OP to the OE development. PMID:25662265

  15. Concordance between vocal and genetic diversity in crested gibbons

    PubMed Central

    2011-01-01

    Background Gibbons or small apes are, next to great apes, our closest living relatives, and form the most diverse group of contemporary hominoids. A characteristic trait of gibbons is their species-specific song structure, which, however, exhibits a certain amount of inter- and intra-individual variation. Although differences in gibbon song structure are routinely applied as taxonomic tool to identify subspecies and species, it remains unclear to which degree acoustic and phylogenetic differences are correlated. To trace this issue, we comparatively analyse song recordings and mitochondrial cytochrome b gene sequence data from 22 gibbon populations representing six of the seven crested gibbon species (genus Nomascus). In addition, we address whether song similarity and geographic distribution can support a recent hypothesis about the biogeographic history of crested gibbons. Results The acoustic analysis of 92 gibbon duets confirms the hypothesised concordance between song structure and phylogeny. Based on features of male and female songs, we can not only distinguish between N. nasutus, N. concolor and the four southern species (N. leucogenys, N. siki, N. annamensis, N. gabriellae), but also between the latter by applying more detailed analysis. In addition to the significant correlation between song structure and genetic similarity, we find a similar high correlation between song similarity and geographic distance. Conclusions The results show that the structure of crested gibbon songs is not only a reliable tool to verify phylogenetic relatedness, but also to unravel geographic origins. As vocal production in other nonhuman primate species appears to be evolutionarily based, it is likely that loud calls produced by other species can serve as characters to elucidate phylogenetic relationships. PMID:21299843

  16. [The Evolutionary Origin of Placodes and Neural Crest Cells

    NASA Technical Reports Server (NTRS)

    Bronner-Fraser, Marianne

    2003-01-01

    The long-term goal of this NASA-supported research is to understand the evolutionary origin of placodes and neural crest cells, with particular reference to evolution of the inner ear, and their evolutionary and developmental relationships. The cephalochordcate amphioxus, the closest living invertebrate relative of the vertebrates is used as a stand-in for the ancestral vertebrate. The research, which has supported one graduate student, Jr-Kai Yu, has resulted in ten publications by the Holland laboratory in peer-reviewed journals.

  17. Tinea Incognita in a Patient with Crest Syndrome: Case Report.

    PubMed

    Gorgievska-Sukarovska, Biljana; Skerlev, Mihael; Žele-Starčević, Lidija

    2015-01-01

    Tinea incognita is a dermatophytic infection that is difficult to diagnose, usually modified by inappropriate topical or systemic corticosteroid therapy. We report an extensive case of tinea incognita caused by the zoophilic dermatophyte Trichophyton mentagrophytes (var. granulosa) in a 49-year-old female patient with CREST (Calcinosis; Raynaud phenomenon; Esophageal involvement; Sclerodactyly; Teleangiectasia) syndrome. Immunocompromised patients, as well as patients with keratinization disorders, seem to be especially susceptible to dermatophytic infections with atypical clinical presentation that is sometimes bizarre and difficult to recognize. Therefore, close monitoring and mycological skin examination is recommended in order to avoid misdiagnosis and to give the patient the best chance of recovery. PMID:26476904

  18. Double-crested cormorants along the upper Mississippi River

    USGS Publications Warehouse

    Kirsch, E.M.

    1995-01-01

    The Upper Mississippi River is an important habitat corridor for migratory birds and other wildlife, and it supports an important commercial and sport fishery. A study was initiated by the U.S. Fish and Wildlife Service in 1991 to describe Double-crested cormorant (Phalacrocorax auritus) distribution and abundance on the Upper Mississippi River throughout the year to better understand the possible impacts of cormorants on fish resources and populations of other piscivorous birds. Double-crested Cormorants were common breeders and abundant during migration on the Upper Mississippi River during the 1940s. Numbers of cormorants declined in the 1960s and 1970s along the Upper Mississippi River as they did in other parts of the United States. In 1992, 418 cormorant pairs were estimated to have nested in four colonies on the Upper Mississippi River, and less than 7,000 cormorants were estimated to have migrated along the river during the fall and spring of 1991 and 1992. Recent public concern for fish resources has grown with a perceived growth of the local cormorant population. Migrating cormorants collected on the Upper Mississippi River took Gizzard Shad (Dorosoma cepedianum) primarily, but chicks were fed a wide variety of fish species.

  19. How Tissue Mechanical Properties Affect Enteric Neural Crest Cell Migration

    PubMed Central

    Chevalier, N.R.; Gazguez, E.; Bidault, L.; Guilbert, T.; Vias, C.; Vian, E.; Watanabe, Y.; Muller, L.; Germain, S.; Bondurand, N.; Dufour, S.; Fleury, V.

    2016-01-01

    Neural crest cells (NCCs) are a population of multipotent cells that migrate extensively during vertebrate development. Alterations to neural crest ontogenesis cause several diseases, including cancers and congenital defects, such as Hirschprung disease, which results from incomplete colonization of the colon by enteric NCCs (ENCCs). We investigated the influence of the stiffness and structure of the environment on ENCC migration in vitro and during colonization of the gastrointestinal tract in chicken and mouse embryos. We showed using tensile stretching and atomic force microscopy (AFM) that the mesenchyme of the gut was initially soft but gradually stiffened during the period of ENCC colonization. Second-harmonic generation (SHG) microscopy revealed that this stiffening was associated with a gradual organization and enrichment of collagen fibers in the developing gut. Ex-vivo 2D cell migration assays showed that ENCCs migrated on substrates with very low levels of stiffness. In 3D collagen gels, the speed of the ENCC migratory front decreased with increasing gel stiffness, whereas no correlation was found between porosity and ENCC migration behavior. Metalloprotease inhibition experiments showed that ENCCs actively degraded collagen in order to progress. These results shed light on the role of the mechanical properties of tissues in ENCC migration during development. PMID:26887292

  20. Determinants of immigration strategies in male crested macaques (Macaca nigra).

    PubMed

    Marty, Pascal R; Hodges, Keith; Agil, Muhammad; Engelhardt, Antje

    2016-01-01

    Immigration into a new group can produce substantial costs due to resistance from residents, but also reproductive benefits. Whether or not individuals base their immigration strategy on prospective cost-benefit ratios remains unknown. We investigated individual immigration decisions in crested macaques, a primate species with a high reproductive skew in favour of high-ranking males. We found two different strategies. Males who achieved low rank in the new group usually immigrated after another male had immigrated within the previous 25 days and achieved high rank. They never got injured but also had low prospective reproductive success. We assume that these males benefitted from immigrating into a destabilized male hierarchy. Males who achieved high rank in the new group usually immigrated independent of previous immigrations. They recieved injuries more frequently and therefore bore immigration costs. They, however, also had higher reproductive success prospects. We conclude that male crested macaques base their immigration strategy on relative fighting ability and thus potential rank in the new group i.e. potential reproductive benefits, as well as potential costs of injury. PMID:27535622

  1. How Tissue Mechanical Properties Affect Enteric Neural Crest Cell Migration

    NASA Astrophysics Data System (ADS)

    Chevalier, N. R.; Gazguez, E.; Bidault, L.; Guilbert, T.; Vias, C.; Vian, E.; Watanabe, Y.; Muller, L.; Germain, S.; Bondurand, N.; Dufour, S.; Fleury, V.

    2016-02-01

    Neural crest cells (NCCs) are a population of multipotent cells that migrate extensively during vertebrate development. Alterations to neural crest ontogenesis cause several diseases, including cancers and congenital defects, such as Hirschprung disease, which results from incomplete colonization of the colon by enteric NCCs (ENCCs). We investigated the influence of the stiffness and structure of the environment on ENCC migration in vitro and during colonization of the gastrointestinal tract in chicken and mouse embryos. We showed using tensile stretching and atomic force microscopy (AFM) that the mesenchyme of the gut was initially soft but gradually stiffened during the period of ENCC colonization. Second-harmonic generation (SHG) microscopy revealed that this stiffening was associated with a gradual organization and enrichment of collagen fibers in the developing gut. Ex-vivo 2D cell migration assays showed that ENCCs migrated on substrates with very low levels of stiffness. In 3D collagen gels, the speed of the ENCC migratory front decreased with increasing gel stiffness, whereas no correlation was found between porosity and ENCC migration behavior. Metalloprotease inhibition experiments showed that ENCCs actively degraded collagen in order to progress. These results shed light on the role of the mechanical properties of tissues in ENCC migration during development.

  2. Isotopic Discrimination in the Double-Crested Cormorant (Phalacrocorax auritus).

    PubMed

    Craig, Elizabeth C; Dorr, Brian S; Hanson-Dorr, Katie C; Sparks, Jed P; Curtis, Paul D

    2015-01-01

    The diet-tissue discrimination factor is the amount by which a consumer's tissue varies isotopically from its diet, and is therefore a key element in models that use stable isotopes to estimate diet composition. In this study we measured discrimination factors in blood (whole blood, red blood cells and plasma), liver, muscle and feathers of Double-crested Cormorants (Phalacrocorax auritus) for stable isotope ratios of carbon, nitrogen and sulfur. Cormorants exhibited discrimination factors that differed significantly among tissue types (for carbon and nitrogen), and differed substantially (in the context of the isotopic variation among relevant prey species) from those observed in congeneric species. The Double-crested Cormorant has undergone rapid population expansion throughout much of its historic range over the past three decades, leading to both real and perceived conflicts with fisheries throughout North America, and this study provides an essential link for the use of stable isotope analysis in researching foraging ecology, diet, and resource use of this widespread and controversial species. PMID:26473353

  3. Erosional decay of the Yucca Mountain crest, Nevada

    NASA Astrophysics Data System (ADS)

    Stüwe, K.; Robl, J.; Matthai, S.

    2009-07-01

    A simple numerical landscape evolution model is used to investigate the rate of erosional decay of the Yucca Mountain crest in Nevada, USA — a location proposed as a permanent repository for high level radioactive waste. The model is based on a stream power approach in which we assume that the rate of erosion is proportional to the size of the catchment as a proxy for water flux and to the square of the topographic gradient. The proportionality constants in the model are determined using the structural history of the region: extensional tectonics has dissected the region into a series of well-defined tilt blocks in the last 11 my and the ratio of fault displacement and gully incision during this time is used to scale the model. Forward predictions of our model into the future show that the crest will denude to the level of the proposed site between 500,000 years and 5 my. This prediction is based on conservative estimates for all involved parameters. Erosion may be more rapid if other processes are involved. For example, our model does not consider continuing uplift or catastrophic surface processes as they have been recorded in the region. We conclude that any "total system performance analysis" (TSPA — as has been performed for the Yucca Mountain region to predict geological events inside the ridge) must consider erosion as an integral part of its predictions.

  4. Endothelial cells regulate neural crest and second heart field morphogenesis

    PubMed Central

    Milgrom-Hoffman, Michal; Michailovici, Inbal; Ferrara, Napoleone; Zelzer, Elazar; Tzahor, Eldad

    2014-01-01

    ABSTRACT Cardiac and craniofacial developmental programs are intricately linked during early embryogenesis, which is also reflected by a high frequency of birth defects affecting both regions. The molecular nature of the crosstalk between mesoderm and neural crest progenitors and the involvement of endothelial cells within the cardio–craniofacial field are largely unclear. Here we show in the mouse that genetic ablation of vascular endothelial growth factor receptor 2 (Flk1) in the mesoderm results in early embryonic lethality, severe deformation of the cardio–craniofacial field, lack of endothelial cells and a poorly formed vascular system. We provide evidence that endothelial cells are required for migration and survival of cranial neural crest cells and consequently for the deployment of second heart field progenitors into the cardiac outflow tract. Insights into the molecular mechanisms reveal marked reduction in Transforming growth factor beta 1 (Tgfb1) along with changes in the extracellular matrix (ECM) composition. Our collective findings in both mouse and avian models suggest that endothelial cells coordinate cardio–craniofacial morphogenesis, in part via a conserved signaling circuit regulating ECM remodeling by Tgfb1. PMID:24996922

  5. Determinants of immigration strategies in male crested macaques (Macaca nigra)

    PubMed Central

    Marty, Pascal R.; Hodges, Keith; Agil, Muhammad; Engelhardt, Antje

    2016-01-01

    Immigration into a new group can produce substantial costs due to resistance from residents, but also reproductive benefits. Whether or not individuals base their immigration strategy on prospective cost-benefit ratios remains unknown. We investigated individual immigration decisions in crested macaques, a primate species with a high reproductive skew in favour of high-ranking males. We found two different strategies. Males who achieved low rank in the new group usually immigrated after another male had immigrated within the previous 25 days and achieved high rank. They never got injured but also had low prospective reproductive success. We assume that these males benefitted from immigrating into a destabilized male hierarchy. Males who achieved high rank in the new group usually immigrated independent of previous immigrations. They recieved injuries more frequently and therefore bore immigration costs. They, however, also had higher reproductive success prospects. We conclude that male crested macaques base their immigration strategy on relative fighting ability and thus potential rank in the new group i.e. potential reproductive benefits, as well as potential costs of injury. PMID:27535622

  6. How Tissue Mechanical Properties Affect Enteric Neural Crest Cell Migration.

    PubMed

    Chevalier, N R; Gazguez, E; Bidault, L; Guilbert, T; Vias, C; Vian, E; Watanabe, Y; Muller, L; Germain, S; Bondurand, N; Dufour, S; Fleury, V

    2016-01-01

    Neural crest cells (NCCs) are a population of multipotent cells that migrate extensively during vertebrate development. Alterations to neural crest ontogenesis cause several diseases, including cancers and congenital defects, such as Hirschprung disease, which results from incomplete colonization of the colon by enteric NCCs (ENCCs). We investigated the influence of the stiffness and structure of the environment on ENCC migration in vitro and during colonization of the gastrointestinal tract in chicken and mouse embryos. We showed using tensile stretching and atomic force microscopy (AFM) that the mesenchyme of the gut was initially soft but gradually stiffened during the period of ENCC colonization. Second-harmonic generation (SHG) microscopy revealed that this stiffening was associated with a gradual organization and enrichment of collagen fibers in the developing gut. Ex-vivo 2D cell migration assays showed that ENCCs migrated on substrates with very low levels of stiffness. In 3D collagen gels, the speed of the ENCC migratory front decreased with increasing gel stiffness, whereas no correlation was found between porosity and ENCC migration behavior. Metalloprotease inhibition experiments showed that ENCCs actively degraded collagen in order to progress. These results shed light on the role of the mechanical properties of tissues in ENCC migration during development. PMID:26887292

  7. Isotopic Discrimination in the Double-Crested Cormorant (Phalacrocorax auritus)

    PubMed Central

    Craig, Elizabeth C.; Sparks, Jed P.; Curtis, Paul D.

    2015-01-01

    The diet-tissue discrimination factor is the amount by which a consumer’s tissue varies isotopically from its diet, and is therefore a key element in models that use stable isotopes to estimate diet composition. In this study we measured discrimination factors in blood (whole blood, red blood cells and plasma), liver, muscle and feathers of Double-crested Cormorants (Phalacrocorax auritus) for stable isotope ratios of carbon, nitrogen and sulfur. Cormorants exhibited discrimination factors that differed significantly among tissue types (for carbon and nitrogen), and differed substantially (in the context of the isotopic variation among relevant prey species) from those observed in congeneric species. The Double-crested Cormorant has undergone rapid population expansion throughout much of its historic range over the past three decades, leading to both real and perceived conflicts with fisheries throughout North America, and this study provides an essential link for the use of stable isotope analysis in researching foraging ecology, diet, and resource use of this widespread and controversial species. PMID:26473353

  8. Ephrin-as cooperate with EphA4 to promote trunk neural crest migration.

    PubMed

    McLennan, R; Krull, C E

    2002-01-01

    Trunk neural crest cells delaminate from the dorsal neural tube and migrate on two distinct pathways: a dorsolateral route, between the ectoderm and somites,and a ventromedial route, through the somitic mesoderm. Neural crest cells that migrate ventromedially travel in a segmental manner through rostral half-somites, avoiding caudal halves. Recent studies demonstrate that various molecular cues guide the migration of neural crest cells, primarily by serving as inhibitors to premature pathway entry orby preventing neural crest from entering inappropriate territories. Trajectories of migrating trunk neural crest are well organized and generally linear in nature, suggesting that positive, migration-promoting factors may be responsible for this organized cell behavior. However, the identity of these factors and their function are not well understood. Here we examine the expression of members of the EphA subclass of receptor tyrosine kinases and ephrins using RT-PCR and immunocytochemistry. Neural crest cells express ephrins and EphA4 at distinct stages during their migration. In functional analyses, addition of ephrin-A2-, ephrin-A5-, and EphA4-Fc disrupted the segmental organization of trunk neural crest migration in explants: neural crest cells entered rostral and caudal halves of somites. Finally, to test the specific effects of these factors on cell behavior, neural crest cells were exposed in vitro to substrate-bound EphA and ephrin-As. Surprisingly, neural crest cells avoided ephrin-A2 or ephrin-A5 substrates; this avoidance was abolished by the addition of EphA4. Together, these data suggest that ephrin-As and EphA4 cooperate to positively promote the migration of neural crest cells through rostral half somites in vivo. PMID:12450221

  9. Enteric Neurospheres Are Not Specific to Neural Crest Cultures: Implications for Neural Stem Cell Therapies

    PubMed Central

    Cooper, Julie; Kronfli, Rania; Cananzi, Mara; Delalande, Jean-Marie; McCann, Conor; Burns, Alan J.; Thapar, Nikhil

    2015-01-01

    Objectives Enteric neural stem cells provide hope of curative treatment for enteric neuropathies. Current protocols for their harvesting from humans focus on the generation of ‘neurospheres’ from cultures of dissociated gut tissue. The study aims to better understand the derivation, generation and composition of enteric neurospheres. Design Gut tissue was obtained from Wnt1-Cre;Rosa26Yfp/Yfp transgenic mice (constitutively labeled neural crest cells) and paediatric patients. Gut cells were cultured either unsorted (mixed neural crest/non-neural crest), or following FACS selection into neural crest (murine-YFP+ve/human-p75+ve) or non-neural crest (YFP-ve/p75-ve) populations. Cultures and resultant neurospheres were characterized using immunolabelling in vitro and following transplantation in vivo. Results Cultures of (i) unsorted, (ii) neural crest, and (iii) non-neural crest cell populations generated neurospheres similar in numbers, size and morphology. Unsorted neurospheres were highly heterogeneous for neural crest content. Neural crest-derived (YFP+ve/p75+ve) neurospheres contained only neural derivatives (neurons and glia) and were devoid of non-neural cells (i.e. negative for SMA, c-Kit), with the converse true for non-neural crest-derived (YFP-ve/p75-ve) ‘neurospheres’. Under differentiation conditions only YFP+ve cells gave rise to neural derivatives. Both YFP+ve and YFP-ve cells displayed proliferation and spread upon transplantation in vivo, but YFP-ve cells did not locate or integrate within the host ENS. Conclusions Spherical accumulations of cells, so-called ‘neurospheres’ forming in cultures of dissociated gut contain variable proportions of neural crest-derived cells. If they are to be used for ENS cell replacement therapy then improved protocols for their generation, including cell selection, should be sought in order to avoid inadvertent transplantation of non-therapeutic, non-ENS cells. PMID:25799576

  10. Influence and timing of arrival of murine neural crest on pancreatic beta cell development and maturation.

    PubMed

    Plank, Jennifer L; Mundell, Nathan A; Frist, Audrey Y; LeGrone, Alison W; Kim, Thomas; Musser, Melissa A; Walter, Teagan J; Labosky, Patricia A

    2011-01-15

    Interactions between cells from the ectoderm and mesoderm influence development of the endodermally-derived pancreas. While much is known about how mesoderm regulates pancreatic development, relatively little is understood about how and when the ectodermally-derived neural crest regulates pancreatic development and specifically, beta cell maturation. A previous study demonstrated that signals from the neural crest regulate beta cell proliferation and ultimately, beta cell mass. Here, we expand on that work to describe timing of neural crest arrival at the developing pancreatic bud and extend our knowledge of the non-cell autonomous role for neural crest derivatives in the process of beta cell maturation. We demonstrated that murine neural crest entered the pancreatic mesenchyme between the 26 and 27 somite stages (approximately 10.0 dpc) and became intermingled with pancreatic progenitors as the epithelium branched into the surrounding mesenchyme. Using a neural crest-specific deletion of the Forkhead transcription factor Foxd3, we ablated neural crest cells that migrate to the pancreatic primordium. Consistent with previous data, in the absence of Foxd3, and therefore the absence of neural crest cells, proliferation of insulin-expressing cells and insulin-positive area are increased. Analysis of endocrine cell gene expression in the absence of neural crest demonstrated that, although the number of insulin-expressing cells was increased, beta cell maturation was significantly impaired. Decreased MafA and Pdx1 expression illustrated the defect in beta cell maturation; we discovered that without neural crest, there was a reduction in the percentage of insulin-positive cells that co-expressed Glut2 and Pdx1 compared to controls. In addition, transmission electron microscopy analyses revealed decreased numbers of characteristic insulin granules and the presence of abnormal granules in insulin-expressing cells from mutant embryos. Together, these data demonstrate that

  11. Influence and timing of arrival of murine neural crest on pancreatic beta cell development and maturation

    PubMed Central

    Plank, Jennifer L.; Mundell, Nathan A.; Frist, Audrey Y.; LeGrone, Alison W.; Kim, Thomas; Musser, Melissa A.; Walter, Teagan J.; Labosky, Patricia A.

    2010-01-01

    Interactions between cells from the ectoderm and mesoderm influence development of the endodermally-derived pancreas. While much is known about how mesoderm regulates pancreatic development, relatively little is understood about how and when the ectodermally-derived neural crest regulates pancreatic development and specifically, beta cell maturation. A previous study demonstrated that signals from the neural crest regulate beta cell proliferation and ultimately, beta cell mass. Here, we expand on that work to describe timing of neural crest arrival at the developing pancreatic bud and extend our knowledge of the non-cell autonomous role for neural crest derivatives in the process of beta cell maturation. We demonstrated that murine neural crest entered the pancreatic mesenchyme between the 26 and 27 somite stages (approximately 10.0 dpc) and became intermingled with pancreatic progenitors as the epithelium branched into the surrounding mesenchyme. Using a neural crest-specific deletion of the Forkhead transcription factor Foxd3, we ablated neural crest cells that migrate to the pancreatic primordium. Consistent with previous data, in the absence of Foxd3, and therefore the absence of neural crest cells, proliferation of Insulin-expressing cells and Insulin-positive area are increased. Analysis of endocrine cell gene expression in the absence of neural crest demonstrated that, although the number of Insulin-expressing cells was increased, beta cell maturation was significantly impaired. Decreased MafA and Pdx1 expression illustrated the defect in beta cell maturation; we discovered that without neural crest, there was a reduction in the percentage of Insulin-positive cells that co-expressed Glut2 and Pdx1 compared to controls. In addition, transmission electron microscopy analyses revealed decreased numbers of characteristic Insulin granules and the presence of abnormal granules in Insulin-expressing cells from mutant embryos. Together, these data demonstrate that

  12. Stage-dependent plasticity of the anterior neural folds to form neural crest.

    PubMed

    Ezin, Maxellende; Barembaum, Meyer; Bronner, Marianne E

    2014-01-01

    The anterior neural fold (ANF) is the only region of the neural tube that does not produce neural crest cells. Instead, ANF cells contribute to the olfactory and lens placodes, as well as to the forebrain and epidermis. Here, we test the ability of the ANF to form neural crest by performing heterotopic transplantation experiments in the chick embryo. We find that, at the neurula stage (HH stage 7), the chick ANF retains the ability to form migrating neural crest cells when transplanted caudally to rostral hindbrain levels. This ability is gradually lost, such that by HH9, this tissue appears to no longer have the potential to form neural crest. In contrast to the ANF, hindbrain dorsal neural folds transplanted rostrally fail to contribute to the olfactory placode but instead continue to generate neural crest cells. The transcription factor GANF is expressed in the ANF and its morpholino-mediated knock-down expands the neural crest domain rostrally and results in the production of migratory cells emerging from the ANF; however, these cells fail to express the HNK1 neural crest marker, suggesting only partial conversion. Our results show that environmental factors can imbue the chick anterior neural folds to assume a neural crest cell fate via a mechanism that partially involves loss of GANF. PMID:25264214

  13. Factors associated with native vegetation recruitment into established crested wheatgrass stands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crested wheatgrass (Agropyron cristatum and Agropyron desertorum) is an introduced perennial grass that has been seeded on over 5 million hectares in semiarid and arid regions of western North America. Crested wheatgrass has been used to stabilize soil following disturbance, increase forage producti...

  14. 77 FR 4274 - Migratory Bird Permits; Double-Crested Cormorant Management in the United States

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-27

    ... governing double-crested cormorant management (76 FR 69225). We requested comments on a variety of issues... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 21 RIN 1018-AX82 Migratory Bird Permits; Double-Crested...

  15. Potential for the Improvement of Turf Quality in Crested Wheatgrass for Low-Maintenance Conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential use of crested wheatgrass (Agropyron cristatum (L.) Gaertn.) as turfgrass has lately received increased attention. Although, crested wheatgrass has many desirable characteristics in semi-arid environments and might be a promising candidate for lower-water use turf, it also has undesir...

  16. Neural crest and placode interaction during the development of the cranial sensory system.

    PubMed

    Steventon, Ben; Mayor, Roberto; Streit, Andrea

    2014-05-01

    In the vertebrate head, the peripheral components of the sensory nervous system are derived from two embryonic cell populations, the neural crest and cranial sensory placodes. Both arise in close proximity to each other at the border of the neural plate: neural crest precursors abut the future central nervous system, while placodes originate in a common preplacodal region slightly more lateral. During head morphogenesis, complex events organise these precursors into functional sensory structures, raising the question of how their development is coordinated. Here we review the evidence that neural crest and placode cells remain in close proximity throughout their development and interact repeatedly in a reciprocal manner. We also review recent controversies about the relative contribution of the neural crest and placodes to the otic and olfactory systems. We propose that a sequence of mutual interactions between the neural crest and placodes drives the coordinated morphogenesis that generates functional sensory systems within the head. PMID:24491819

  17. Toxoplasma gondii in an African crested porcupine (Hystrix cristata).

    PubMed

    Harrison, Tara M; Moorman, Jamee Black; Bolin, Steven R; Grosjean, Nicole L; Lim, Ailam; Fitzgerald, Scott D

    2007-03-01

    An adult female crested porcupine (Hystrix cristata) was evaluated for acute onset of neurologic signs including head tilt, circling, and ataxia. She was found dead in her holding area 2 days after initially exhibiting clinical signs. Necropsy was unremarkable. Histopathology of brain tissue revealed the presence of protozoal cysts associated with inflammation as the underlying cause of clinical signs and death. Immunohistochemical staining of brain tissue for Toxoplasma gondii was strongly positive. PCR on fresh brain confirmed T. gondii as the causative organism. An adult male in the same enclosure has demonstrated similar neurologic signs over the past 3 years and has failed to respond to various medical treatments. Clinical disease associated with T. gondii has not been previously reported in this porcupine species or any other Old World porcupines, although there are several reports of clinical toxoplasmosis involving New World porcupine species. PMID:17402616

  18. Diet of double-crested cormorants wintering in Texas

    USGS Publications Warehouse

    Campo, J.J.; Thompson, B.C.; Barron, J.C.; Telfair II, R. C.; Durocher, P.; Gutreuter, S.

    1993-01-01

    The diets of 420 Double-crested Cormorants (Phalacrocorax auritus) were studied during November 1986-March 1987 on eight public reservoirs in Texas. Prey included 29 fish species and the mean live weight of fish per bird was 122 g. Fishes a??415 mm long were ingested, but those a??125 mm accounted for 90% of cormorant food contents by number. Shad (Dorosoma spp.) and sunfishes (Lepomis spp.) accounted for 90% of the total food items by number. Consumption of fishes (percent by weight) was different for male vs. female and adult vs. juvenile cormorants. Total consumption of fish by weight was consistent throughout the period; however, fewer but much larger fish were consumed after 15 February. Cormorants ate fishes that were most abundant in reservoirs. Sport fishes made up a substantial portion of cormorant food by weight, but not by number on some reservoirs. Cormorants ate very few large sport fish, however.

  19. Epithelial–Mesenchymal Transitions during Neural Crest and Somite Development

    PubMed Central

    Kalcheim, Chaya

    2015-01-01

    Epithelial-to-mesenchymal transition (EMT) is a central process during embryonic development that affects selected progenitor cells of all three germ layers. In addition to driving the onset of cellular migrations and subsequent tissue morphogenesis, the dynamic conversions of epithelium into mesenchyme and vice-versa are intimately associated with the segregation of homogeneous precursors into distinct fates. The neural crest and somites, progenitors of the peripheral nervous system and of skeletal tissues, respectively, beautifully illustrate the significance of EMT to the above processes. Ongoing studies progressively elucidate the gene networks underlying EMT in each system, highlighting the similarities and differences between them. Knowledge of the mechanistic logic of this normal ontogenetic process should provide important insights to the understanding of pathological conditions such as cancer metastasis, which shares some common molecular themes. PMID:26712793

  20. The Connections Between Neural Crest Development and Neuroblastoma

    PubMed Central

    Jiang, Manrong; Stanke, Jennifer; Lahti, Jill M.

    2013-01-01

    Neuroblastoma (NB), the most common extracranial solid tumor in childhood, is an extremely heterogeneous disease both biologically and clinically. Although significant progress has been made in identifying molecular and genetic markers for NB, this disease remains an enigmatic challenge. Since NB is thought to be an embryonal tumor that is derived from precursor cells of the peripheral (sympathetic) nervous system, understanding the development of normal sympathetic nervous system may highlight abnormal events that contribute to NB initiation. Therefore, this review focuses on the development of the peripheral trunk neural crest, the current understanding of how developmental factors may contribute to NB and on recent advances in the identification of important genetic lesions and signaling pathways involved in NB tumorigenesis and metastasis. Finally, we discuss how future advances in identification of molecular alterations in NB may lead to more effective, less toxic therapies, and improve the prognosis for NB patients. PMID:21295685

  1. Hycrest crested wheatgrass accelerates the degradation of pentachlorophenol in soil

    NASA Technical Reports Server (NTRS)

    Ferro, A. M.; Sims, R. C.; Bugbee, B.

    1994-01-01

    We investigated the effects of vegetation on the fate of pentachlorophenol (PCP) in soil using a novel high-flow sealed test system. Pentachlorophenol has been widely used as a wood preservative, and this highly toxic biocide contaminates soil and ground water at many sites. Although plants are known to accelerate the rates of degradation of certain soil contaminants, this approach has not been thoroughly investigated for PCP. The fate of [14C]PCP, added to soil at a concentration of 100 mg/kg, was compared in three unplanted and three planted systems. The plant used was Hycrest, a perennial, drought-tolerant cultivar of crested wheatgrass [Agropyron desertorum (Fischer ex Link) Schultes]. The flow-through test system allowed us to maintain a budget for 14C-label as well as monitor mineralization (breakdown to 14CO2) and volatilization of the test compound in a 155-d trial. In the unplanted systems, an average of 88% of the total radiolabel remained in the soil and leachate and only 6% was mineralized. In the planted system, 33% of the radiolabel remained in the soil plus leachate, 22% was mineralized, and 36% was associated with plant tissue (21% with the root fraction and 15% with shoots). Mineralization rates were 23.1 mg PCP mineralized kg-1 soil in 20 wk in the planted system, and for the unplanted system 6.6 mg PCP kg-1 soil for the same time period. Similar amounts of volatile organic material were generated in the two systems (1.5%). Results indicated that establishing crested wheatgrass on PCP-contaminated surface soils may accelerate the removal of the contaminant.

  2. Control of neural crest cell dispersion in the trunk of the avian embryo.

    PubMed

    Erickson, C A

    1985-09-01

    Many hypotheses have been advanced to explain the orientation and directional migration of neural crest cells. These include positive and negative chemotaxis, haptotaxis, galvanotaxis, and contact inhibition. To test directly the factors that may control the directional dispersion of the neural crest, I have employed a variety of grafting techniques in living embryos. In addition, time-lapse video microscopy has been used to study neural crest cells in tissue culture. Trunk neural crest cells normally disperse from their origin at the dorsal neural tube along two extracellular pathways. One pathway extends laterally between the ectoderm and somites. When either pigmented neural crest cells or neural crest cells isolated from 24-hr cultures are grafted into the space lateral to the somites, they migrate: (1) medially toward the neural tube in the space between the ectoderm and somites and (2) ventrally along intersomitic blood vessels. Once the grafted cells contact the posterior cardinal vein and dorsal aorta they migrate along both blood vessels for several somite lengths in the anterior-posterior axis. Neural crest cells grafted lateral to the somites do not immediately move laterally into the somatic mesoderm of the body wall or the limb. Dispersion of neural crest cells into the mesoderm occurs only after blood vessels and nerves have first invaded, which the grafted cells then follow. The other neural crest pathway extends ventrally alongside the neural tube in the intersomitic space. When neural crest cells were grafted to a ventral position, between the notochord and dorsal aorta, in this intersomitic pathway at the axial level of the last somite, the grafted cells migrate rapidly within 2 hr in two directions: (1) dorsally, in the intersomitic space, until the grafted cells contact the ventrally moving stream of the host neural crest and (2) laterally, along the dorsal aorta and endoderm. All of the above experiments indicate that neither a preestablished

  3. The ‘Unicorn’ Dinosaur That Wasn’t: A New Reconstruction of the Crest of Tsintaosaurus and the Early Evolution of the Lambeosaurine Crest and Rostrum

    PubMed Central

    Prieto-Márquez, Albert; Wagner, Jonathan R.

    2013-01-01

    The lambeosaurine Tsintaosaurus spinorhinus has traditionally been reconstructed with an elevated, hollow, spike-like crest composed entirely of the nasal bones, although this has been disputed. Here, we provide a new reconstruction of the skull of this species based on reexamination and reinterpretation of the morphology and articular relationships of the type and Paratype skulls and a fragmentary crest. We confirm the presence of a supracranial crest composed of the elevated nasal bones, but also including the premaxillae. We hypothesize that the crest is a tall, lobate, hollow structure that projects dorsally and slightly caudally a distance greater than the height of the skull along the quadrate. In our reconstruction, the nasal passage passes through the crest, but enters the skull rostral to the tubular process of the nasals, not through it. Tsintaosaurus spinorhinus is rediagnosed on the basis of a suite of cranial autapomorphies including a circumnarial fossa subdivided into three accessory fossae, prefrontal with ascending rostral process and lateral flange, nasals fused sagittally to form elongate tubular process that rises dorsally from skull roof, each nasal being expanded rostrocaudally into a rhomboid distal process, and medial processes of premaxillae at the summit of the cranial crest inserted between rhomboid processes of nasals. Tsintaosaurus spinorhinus lacks characters that are present in more derived lambeosaurines (parasaurolophins and lambeosaurins), such as rotation of the caudal margin of the crest to an acute angle with the skull roof, lateral processes of the nasals that enclose part of the intracranial cavity and participate in the formation of the walls of the common median chamber, and a smooth narial fossa lacking ridges and accessory fossae. We hypothesize that ancestrally the rostrum of lambeosaurines may have been more similar to that in Saurolophinae, and became subsequently reduced in complexity during evolution of the group

  4. Diachronic analysis of the occupation of the steppe area of the department of Sidi Bel Abbes (Western Algeria)

    NASA Astrophysics Data System (ADS)

    Hellal, B.; Ayache, A.; Ayad, N.; Hellal, T.

    2016-06-01

    Modes of occupation of the soil of the steppe area of the department of Sidi Bel Abbes (Western Algeria) know lots of mutations during the period 1987/2013; compromising the future of pastoral activity. This dissection based on supervised classification TSAVI values (Transformed Soil Adjusted Vegetation Index) using images of remote sensing of average spatial resolution of type Landsat-TM 5 and 8. The determination of the state of occupation of the ground and validation of remote sensing map shows that the status of the halophytic/psammophytic steppes and the Matorrals are detected in 38.38 % and 55,71 % of cases, respectively. On the other hand, the steppes chamaephytic mark -9,81 % regression only, agricultural land -24,51 %, and -46,24 % dense vegetation are correctly mapped. The sensing medium resolution is therefore, in the light of these figures, a management tool of the steppe field relevant and effective, which, in addition, allows enriching the field for a proper plan for the fight against desertification.

  5. Amphioxus and lamprey AP-2 genes: implications for neural crest evolution and migration patterns

    NASA Technical Reports Server (NTRS)

    Meulemans, Daniel; Bronner-Fraser, Marianne

    2002-01-01

    The neural crest is a uniquely vertebrate cell type present in the most basal vertebrates, but not in cephalochordates. We have studied differences in regulation of the neural crest marker AP-2 across two evolutionary transitions: invertebrate to vertebrate, and agnathan to gnathostome. Isolation and comparison of amphioxus, lamprey and axolotl AP-2 reveals its extensive expansion in the vertebrate dorsal neural tube and pharyngeal arches, implying co-option of AP-2 genes by neural crest cells early in vertebrate evolution. Expression in non-neural ectoderm is a conserved feature in amphioxus and vertebrates, suggesting an ancient role for AP-2 genes in this tissue. There is also common expression in subsets of ventrolateral neurons in the anterior neural tube, consistent with a primitive role in brain development. Comparison of AP-2 expression in axolotl and lamprey suggests an elaboration of cranial neural crest patterning in gnathostomes. However, migration of AP-2-expressing neural crest cells medial to the pharyngeal arch mesoderm appears to be a primitive feature retained in all vertebrates. Because AP-2 has essential roles in cranial neural crest differentiation and proliferation, the co-option of AP-2 by neural crest cells in the vertebrate lineage was a potentially crucial event in vertebrate evolution.

  6. Cadherin-6B undergoes macropinocytosis and clathrin-mediated endocytosis during cranial neural crest cell EMT

    PubMed Central

    Padmanabhan, Rangarajan; Taneyhill, Lisa A.

    2015-01-01

    The epithelial-to-mesenchymal transition (EMT) is important for the formation of migratory neural crest cells during development and is co-opted in human diseases such as cancer metastasis. Chick premigratory cranial neural crest cells lose intercellular contacts, mediated in part by Cadherin-6B (Cad6B), migrate extensively, and later form a variety of adult derivatives. Importantly, modulation of Cad6B is crucial for proper neural crest cell EMT. Although Cad6B possesses a long half-life, it is rapidly lost from premigratory neural crest cell membranes, suggesting the existence of post-translational mechanisms during EMT. We have identified a motif in the Cad6B cytoplasmic tail that enhances Cad6B internalization and reduces the stability of Cad6B upon its mutation. Furthermore, we demonstrate for the first time that Cad6B is removed from premigratory neural crest cells through cell surface internalization events that include clathrin-mediated endocytosis and macropinocytosis. Both of these processes are dependent upon the function of dynamin, and inhibition of Cad6B internalization abrogates neural crest cell EMT and migration. Collectively, our findings reveal the significance of post-translational events in controlling cadherins during neural crest cell EMT and migration. PMID:25795298

  7. The application of eDNA for monitoring of the Great Crested Newt in the UK

    PubMed Central

    Rees, Helen C; Bishop, Keith; Middleditch, David J; Patmore, James R M; Maddison, Ben C; Gough, Kevin C

    2014-01-01

    Current ecological surveys for great crested newts are time-consuming and expensive and can only be carried out within a short survey window. Additional survey methods which would facilitate the detection of rare or protected species such as the great crested newt (Triturus cristatus) would be extremely advantageous. Environmental DNA (eDNA) analysis has been utilized for the detection of great crested newts in Denmark. Here, the same methodology has been applied to water samples taken from UK ponds concurrently with conventional field surveying techniques. Our eDNA analysis exhibited an 84% success rate with a kappa coefficient of agreement between field and eDNA surveys of 0.86. One pond determined to be negative for great crested newt by field survey was positive by eDNA analysis, revealing the potential for improved detection rates using this methodology. Analysis of water samples collected in late summer indicates that eDNA analysis could be used to detect great crested newt after the optimal survey window for current field techniques had passed. Consequently, eDNA analysis could augment currently stipulated techniques for great crested newt surveying as a relatively quick and inexpensive tool for collecting great crested newt presence and distribution data within the UK instead of or prior to full field surveys. PMID:25505530

  8. Early regulative ability of the neuroepithelium to form cardiac neural crest

    PubMed Central

    Ezin, Akouavi M.; Sechrist, John W.; Zah, Angela; Bronner, Marianne; Fraser, Scott E.

    2010-01-01

    The cardiac neural crest (arising from the level of hindbrain rhombomeres 6–8) contributes to the septation of the cardiac outflow tract and the formation of aortic arches. Removal of this population after neural tube closure results in severe septation defects in the chick, reminiscent of human birth defects. Because neural crest cells from other axial levels have regenerative capacity, we asked whether the cardiac neural crest might also regenerate at early stages in a manner that declines with time. Accordingly, we find that ablation of presumptive cardiac crest at stage 7, as the neural folds elevate, results in reformation of migrating cardiac neural crest by stage 13. Fate mapping reveals that the new population derives largely from the neuroepithelium ventral and rostral to the ablation. The stage of ablation dictates the competence of residual tissue to regulate and regenerate, as this capacity is lost by stage 9, consistent with previous reports. These findings suggest that there is a temporal window during which the presumptive cardiac neural crest has the capacity to regulate and regenerate, but this regenerative ability is lost earlier than in other neural crest populations. PMID:21047505

  9. Slits Affect the Timely Migration of Neural Crest Cells via Robo Receptor

    PubMed Central

    Giovannone, Dion; Reyes, Michelle; Reyes, Rachel; Correa, Lisa; Martinez, Darwin; Ra, Hannah; Gomez, Gustavo; Kaiser, Josh; Ma, Le; Stein, Mary-Pat; de Bellard, Maria Elena

    2013-01-01

    SUMMARY Background Neural crest cells emerge by delamination from the dorsal neural tube and give rise to various components of the peripheral nervous system in vertebrate embryos. These cells change from non-motile into highly motile cells migrating to distant areas before further differentiation. Mechanisms controlling delamination and subsequent migration of neural crest cells are not fully understood. Slit2, a chemorepellant for axonal guidance that repels and stimulates motility of trunk neural crest cells away from the gut has recently been suggested to be a tumor suppressor molecule. The goal of this study was to further investigate the role of Slit2 in trunk neural crest cell migration by constitutive expression in neural crest cells. Results We found that Slit gain-of-function significantly impaired neural crest cell migration while Slit loss-of-function favored migration. In addition, we observed that the distribution of key cytoskeletal markers was disrupted in both gain and loss of function instances. Conclusions These findings suggest that Slit molecules might be involved in the processes that allow neural crest cells to begin migration and transitioning to a mesenchymal type. PMID:22689303

  10. VEGF signals induce trailblazer cell identity that drives neural crest migration.

    PubMed

    McLennan, Rebecca; Schumacher, Linus J; Morrison, Jason A; Teddy, Jessica M; Ridenour, Dennis A; Box, Andrew C; Semerad, Craig L; Li, Hua; McDowell, William; Kay, David; Maini, Philip K; Baker, Ruth E; Kulesa, Paul M

    2015-11-01

    Embryonic neural crest cells travel in discrete streams to precise locations throughout the head and body. We previously showed that cranial neural crest cells respond chemotactically to vascular endothelial growth factor (VEGF) and that cells within the migratory front have distinct behaviors and gene expression. We proposed a cell-induced gradient model in which lead neural crest cells read out directional information from a chemoattractant profile and instruct trailers to follow. In this study, we show that migrating chick neural crest cells do not display distinct lead and trailer gene expression profiles in culture. However, exposure to VEGF in vitro results in the upregulation of a small subset of genes associated with an in vivo lead cell signature. Timed addition and removal of VEGF in culture reveals the changes in neural crest cell gene expression are rapid. A computational model incorporating an integrate-and-switch mechanism between cellular phenotypes predicts migration efficiency is influenced by the timescale of cell behavior switching. To test the model hypothesis that neural crest cellular phenotypes respond to changes in the VEGF chemoattractant profile, we presented ectopic sources of VEGF to the trailer neural crest cell subpopulation and show diverted cell trajectories and stream alterations consistent with model predictions. Gene profiling of trailer cells that diverted and encountered VEGF revealed upregulation of a subset of 'lead' genes. Injection of neuropilin1 (Np1)-Fc into the trailer subpopulation or electroporation of VEGF morpholino to reduce VEGF signaling failed to alter trailer neural crest cell trajectories, suggesting trailers do not require VEGF to maintain coordinated migration. These results indicate that VEGF is one of the signals that establishes lead cell identity and its chemoattractant profile is critical to neural crest cell migration. PMID:26278036

  11. A Src-Tks5 Pathway Is Required for Neural Crest Cell Migration during Embryonic Development

    PubMed Central

    Murphy, Danielle A.; Tsai, Jeff H.; Kawakami, Yasuhiko; Maurer, Jochen; Stewart, Rodney A.; Izpisúa-Belmonte, Juan Carlos; Courtneidge, Sara A.

    2011-01-01

    In the adult organism, cell migration is required for physiological processes such as angiogenesis and immune surveillance, as well as pathological events such as tumor metastasis. The adaptor protein and Src substrate Tks5 is necessary for cancer cell migration through extracellular matrix in vitro and tumorigenicity in vivo. However, a role for Tks5 during embryonic development, where cell migration is essential, has not been examined. We used morpholinos to reduce Tks5 expression in zebrafish embryos, and observed developmental defects, most prominently in neural crest-derived tissues such as craniofacial structures and pigmentation. The Tks5 morphant phenotype was rescued by expression of mammalian Tks5, but not by a variant of Tks5 in which the Src phosphorylation sites have been mutated. We further evaluated the role of Tks5 in neural crest cells and neural crest-derived tissues and found that loss of Tks5 impaired their ventral migration. Inhibition of Src family kinases also led to abnormal ventral patterning of neural crest cells and their derivatives. We confirmed that these effects were likely to be cell autonomous by shRNA-mediated knockdown of Tks5 in a murine neural crest stem cell line. Tks5 was required for neural crest cell migration in vitro, and both Src and Tks5 were required for the formation of actin-rich structures with similarity to podosomes. Additionally, we observed that neural crest cells formed Src-Tks5-dependent cell protrusions in 3-D culture conditions and in vivo. These results reveal an important and novel role for the Src-Tks5 pathway in neural crest cell migration during embryonic development. Furthermore, our data suggests that this pathway regulates neural crest cell migration through the generation of actin-rich pro-migratory structures, implying that similar mechanisms are used to control cell migration during embryogenesis and cancer metastasis. PMID:21799874

  12. Characterization of the Trunk Neural Crest in the bamboo shark, Chiloscyllium punctatum

    PubMed Central

    Juarez, Marilyn; Reyes, Michelle; Coleman, Tiffany; Rotenstein, Lisa; Sao, Sothy; Martinez, Darwin; Jones, Matthew; Mackelprang, Rachel; de Bellard, Maria Elena

    2013-01-01

    The neural crest is a population of mesenchymal cells that after migrating from the neural tube give rise to a structures and cell-types: jaw, part of the peripheral ganglia and melanocytes. Although much is known about neural crest development in jawed vertebrates, a clear picture of trunk neural crest development for elasmobranchs is yet to be developed. Here we present a detailed study of trunk neural crest development in the bamboo shark, Chiloscyllium punctatum. Vital labeling with DiI and in situ hybridization using cloned Sox8 and Sox9 probes demonstrated that trunk neural crest cells follow a pattern similar to the migratory paths already described in zebrafish and amphibians. We found shark trunk neural crest along the rostral side of the somites, the ventromedial pathway, branchial arches, gut, sensory ganglia and nerves. Interestingly, Chiloscyllium punctatum Sox8 and Sox9 sequences aligned with vertebrate SoxE genes, but appeared to be more ancient than the corresponding vertebrate paralogs. The expression of these two SoxE genes in trunk neural crest cells, especially Sox9, matched the Sox10 migratory patterns observed in teleosts. Interestingly, we observed DiI cells and Sox9 labeling along the lateral line, suggesting that in C. punctatum, glial cells in the lateral line are likely of neural crest origin. Though this has been observed in other vertebrates, we are the first to show that the pattern is present in cartilaginous fishes. These findings demonstrate that trunk neural crest cell development in Chiloscyllium punctatum follows the same highly conserved migratory pattern observed in jawed vertebrates PMID:23640803

  13. A Novel Role for Lh3 Dependent ECM Modifications during Neural Crest Cell Migration in Zebrafish

    PubMed Central

    Banerjee, Santanu; Isaacman-Beck, Jesse; Schneider, Valerie A.; Granato, Michael

    2013-01-01

    During vertebrate development, trunk neural crest cells delaminate along the entire length of the dorsal neural tube and initially migrate as a non-segmented sheet. As they enter the somites, neural crest cells rearrange into spatially restricted segmental streams. Extracellular matrix components are likely to play critical roles in this transition from a sheet-like to a stream-like mode of migration, yet the extracellular matrix components and their modifying enzymes critical for this transition are largely unknown. Here, we identified the glycosyltransferase Lh3, known to modify extracellular matrix components, and its presumptive substrate Collagen18A1, to provide extrinsic signals critical for neural crest cells to transition from a sheet-like migration behavior to migrating as a segmental stream. Using live cell imaging we show that in lh3 null mutants, neural crest cells fail to transition from a sheet to a stream, and that they consequently enter the somites as multiple streams, or stall shortly after entering the somites. Moreover, we demonstrate that transgenic expression of lh3 in a small subset of somitic cells adjacent to where neural crest cells switch from sheet to stream migration restores segmental neural crest cell migration. Finally, we show that knockdown of the presumptive Lh3 substrate Collagen18A1 recapitulates the neural crest cell migration defects observed in lh3 mutants, consistent with the notion that Lh3 exerts its effect on neural crest cell migration by regulating post-translational modifications of Collagen18A1. Together these data suggest that Lh3–Collagen18A1 dependent ECM modifications regulate the transition of trunk neural crest cells from a non-segmental sheet like migration mode to a segmental stream migration mode. PMID:23349938

  14. Piezo harvesting of bone grafts from the anterior iliac crest: A technical note

    PubMed Central

    Ylikontiola, Leena P.; Lehtonen, Ville; Sándor, George K.

    2016-01-01

    Background: Autogenous bone graft harvesting from the iliac crest is associated with donor site morbidity. The aim of this report is to describe the use of piezosurgery as an attempt at morbidity reduction. Materials and Methods: A piezosurgical handpiece and its selection of tips can easily be accommodated in an iliac crest wound to osteotomize and allow the harvest and delivery of autogenous bone grafts. Results: Corticocancellous blocks or cancellous strips of autogenous bone can be readily harvested using a piezosurgical technique at the anterior iliac crest. Conclusion: Piezosurgery avoids some of the traumatic aspects of harvesting bone associated with the use of conventional rotary instruments or saws.

  15. Animal models for studying neural crest development: is the mouse different?

    PubMed

    Barriga, Elias H; Trainor, Paul A; Bronner, Marianne; Mayor, Roberto

    2015-05-01

    The neural crest is a uniquely vertebrate cell type and has been well studied in a number of model systems. Zebrafish, Xenopus and chick embryos largely show consistent requirements for specific genes in early steps of neural crest development. By contrast, knockouts of homologous genes in the mouse often do not exhibit comparable early neural crest phenotypes. In this Spotlight article, we discuss these species-specific differences, suggest possible explanations for the divergent phenotypes in mouse and urge the community to consider these issues and the need for further research in complementary systems. PMID:25922521

  16. Methods for derivation of multipotent neural crest cells derived from human pluripotent stem cells

    PubMed Central

    Avery, John; Dalton, Stephen

    2016-01-01

    Summary Multipotent, neural crest cells (NCCs) produce a wide-range of cell types during embryonic development. This includes melanocytes, peripheral neurons, smooth muscle cells, osteocytes, chondrocytes and adipocytes. The protocol described here allows for highly-efficient differentiation of human pluripotent stem cells to a neural crest fate within 15 days. This is accomplished under feeder-free conditions, using chemically defined medium supplemented with two small molecule inhibitors that block glycogen synthase kinase 3 (GSK3) and bone morphogenic protein (BMP) signaling. This technology is well-suited as a platform to understand in greater detail the pathogenesis of human disease associated with impaired neural crest development/migration. PMID:25986498

  17. BMP receptor IA is required in mammalian neural crest cells for development of the cardiac outflow tract and ventricular myocardium

    PubMed Central

    Stottmann, Rolf W.; Choi, Murim; Mishina, Yuji; Meyers, Erik N.; Klingensmith, John

    2010-01-01

    Summary The neural crest is a multipotent, migratory cell population arising from the border of the neural and surface ectoderm. In mouse, the initial migratory neural crest cells occur at the five-somite stage. Bone morphogenetic proteins (BMPs), particularly BMP2 and BMP4, have been implicated as regulators of neural crest cell induction, maintenance, migration, differentiation and survival. Mouse has three known BMP2/4 type I receptors, of which Bmpr1a is expressed in the neural tube sufficiently early to be involved in neural crest development from the outset; however, earlier roles in other domains obscure its requirement in the neural crest. We have ablated Bmpr1a specifically in the neural crest, beginning at the five-somite stage. We find that most aspects of neural crest development occur normally; suggesting that BMPRIA is unnecessary for many aspects of early neural crest biology. However, mutant embryos display a shortened cardiac outflow tract with defective septation, a process known to require neural crest cells and to be essential for perinatal viability. Surprisingly, these embryos die in mid-gestation from acute heart failure, with reduced proliferation of ventricular myocardium. The myocardial defect may involve reduced BMP signaling in a novel, minor population of neural crest derivatives in the epicardium, a known source of ventricular myocardial proliferation signals. These results demonstrate that BMP2/4 signaling in mammalian neural crest derivatives is essential for outflow tract development and may regulate a crucial proliferation signal for the ventricular myocardium. PMID:15073157

  18. Measuring TeV Cosmic-Ray Electrons with CREST

    NASA Astrophysics Data System (ADS)

    Schubnell, M.; Bower, C.; Coutu, S.; DuVernois, M.; McKee, S.; Muller, D.; Musser, J.; Nutter, S.; Swordy, S.; Tarle, G.; Tomasch, A.; Yagi, A.

    2004-08-01

    There is strong indirect evidence for the supernova shock acceleration of galactic cosmic-ray electrons through observations of non-thermal X-rays and TeV gamma rays from supernova remnants (SNRs). Current and past electron detectors, typically flown by high altitude balloons, have been limited in their ability to study high energy electrons in the local cosmic-ray flux by their short exposure times and small apertures. To date, no measurements have been made at energies greater than 2 TeV. Yet the detection of high-energy electrons would be extremely significant, yielding information about the spatial distribution of nearby cosmic ray sources. High-energy electrons lose energy rapidly during propagation in the Galaxy through synchrotron and inverse Compton processes and thus TeV electrons reaching the solar system have to originate at distances < 1 kpc, leaving few known supernova remnants from which these particles could originate. The spectral shape of high-energy electrons should, therefore, be strongly affected by the number of nearby sources, and their distance distribution. Conversely, if no such features in the high-energy electron spectrum are observed it will call into question our understanding of cosmic ray sources and propagation. The balloon-borne Cosmic Ray Electron Synchrotron Telescope (CREST) will detect high-energy electrons by measuring the X-ray synchrotron photons generated by these electrons in the Earth's magnetic field. This technique results in a substantial increase in the acceptance and sensitivity of the apparatus compared to the traditional direct detection of electrons. The instrument will consist of a 2m x 2m array of BGO crystals. Simulation studies indicate that with an ultra-long duration (100 day) flight, as many as 250 such electrons will be detected with energies greater than 2 TeV, with an expected background of only 1 event. A prototype instrument is currently being developed and will be flown in 2005 on a conventional

  19. Crestospheres: Long-Term Maintenance of Multipotent, Premigratory Neural Crest Stem Cells

    PubMed Central

    Kerosuo, Laura; Nie, Shuyi; Bajpai, Ruchi; Bronner, Marianne E.

    2015-01-01

    Summary Premigratory neural crest cells comprise a transient, embryonic population that arises within the CNS, but subsequently migrates away and differentiates into many derivatives. Previously, premigratory neural crest could not be maintained in a multipotent, adhesive state without spontaneous differentiation. Here, we report conditions that enable maintenance of neuroepithelial “crestospheres” that self-renew and retain multipotency for weeks. Moreover, under differentiation conditions, these cells can form multiple derivatives in vitro and in vivo after transplantation into chick embryos. Similarly, human embryonic stem cells directed to a neural crest fate can be maintained as crestospheres and subsequently differentiated into several derivatives. By devising conditions that maintain the premigratory state in vitro, these results demonstrate that neuroepithelial neural crest precursors are capable of long-term self-renewal. This approach will help uncover mechanisms underlying their developmental potential, differentiation and, together with the induced pluripotent stem cell techniques, the pathology of human neurocristopathies. PMID:26441305

  20. Crestospheres: Long-Term Maintenance of Multipotent, Premigratory Neural Crest Stem Cells.

    PubMed

    Kerosuo, Laura; Nie, Shuyi; Bajpai, Ruchi; Bronner, Marianne E

    2015-10-13

    Premigratory neural crest cells comprise a transient, embryonic population that arises within the CNS, but subsequently migrates away and differentiates into many derivatives. Previously, premigratory neural crest could not be maintained in a multipotent, adhesive state without spontaneous differentiation. Here, we report conditions that enable maintenance of neuroepithelial "crestospheres" that self-renew and retain multipotency for weeks. Moreover, under differentiation conditions, these cells can form multiple derivatives in vitro and in vivo after transplantation into chick embryos. Similarly, human embryonic stem cells directed to a neural crest fate can be maintained as crestospheres and subsequently differentiated into several derivatives. By devising conditions that maintain the premigratory state in vitro, these results demonstrate that neuroepithelial neural crest precursors are capable of long-term self-renewal. This approach will help uncover mechanisms underlying their developmental potential, differentiation and, together with the induced pluripotent stem cell techniques, the pathology of human neurocristopathies. PMID:26441305

  1. Seedling Interference and Niche Differentiation Between Crested Wheatgrass and Contrasting Native Great Basin Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interference from crested wheatgrass (Agropyron cristatum [L.} Gaertn.) seedlings is considered a major obstacle to native species establishment; however, estimates of interference at variable seedling densities have not been fully defined. We conducted greenhouse experiments using an addition seri...

  2. Does pond water reflectance influence double-crested cormorant selection of aquaculture pond?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Double-crested cormorants (Phalacrocorax auritus) are a frequent and major avian predator on channel catfish (Ictalurus punctatus) and other aquaculture species throughout the southeastern USA. Although cormorant movements and occurrence within the aquaculture production region are understood, no s...

  3. Oligodendroglial and Pan-neural Crest Expression of Cre Recombinase Directed by Sox10 Enhancer

    PubMed Central

    Stine, Zachary E.; Huynh, Jimmy L.; Loftus, Stacie K.; Gorkin, David U.; Salmasi, Amirali H.; Novak, Thomas; Purves, Todd; Miller, Ronald A.; Antonellis, Anthony; Gearhart, John P.; Pavan, William J.; McCallion, Andrew S.

    2010-01-01

    Utilizing a recently identified Sox10 distal enhancer directing Cre expression, we report S4F:Cre, a transgenic mouse line capable of inducing recombination in oligodendroglia and all examined neural crest derived tissues. Assayed using R26R:LacZ reporter mice expression was detected in neural crest derived tissues including the forming facial skeleton, dorsal root ganglia, sympathetic ganglia, enteric nervous system, aortae and melanoblasts, consistent with Sox10 expression. LacZ reporter expression was also detected in non-neural crest derived tissues including the oligodendrocytes and the ventral neural tube. This line provides appreciable differences in Cre expression pattern from other transgenic mouse lines that mark neural crest populations, including additional populations defined by the expression of other SoxE proteins. The S4F:Cre transgenic line will thus serve as a powerful tool for lineage tracing, gene function characterization and genome manipulation in these populations. PMID:19830815

  4. 76 FR 22393 - Eagle Mountain Pumped Storage Hydroelectric Project, Eagle Crest Energy; Notice of Cancellation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-21

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Eagle Mountain Pumped Storage Hydroelectric Project, Eagle Crest Energy... and Wildlife Service for the proposed Eagle Mountain Pumped Storage Hydroelectric Project....

  5. 78 FR 26358 - Eagle Mountain Pumped Storage Hydroelectric Project, Eagle Crest Energy; Notice of Meeting With...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-06

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Eagle Mountain Pumped Storage Hydroelectric Project, Eagle Crest Energy...), on the Eagle Mountain Pumped Storage Hydroelectric Project. e. All local, state, and federal...

  6. 77 FR 47628 - Eagle Mountain Pumped Storage Hydroelectric Project; Eagle Crest Energy; Notice of Meeting...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-09

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Eagle Mountain Pumped Storage Hydroelectric Project; Eagle Crest Energy... Management Act and the Federal Power Act), on the Eagle Mountain Pumped Storage Hydroelectric...

  7. Clarifying Potential Successional Trajectories in Sagebrush Communities Historically Seeded with Crested Wheatgrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crested wheatgrass (Agropyron cristatum [L.] Gaertn.) has been historically seeded on thousands of hectares of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingenis) communities. Initially used to improve degraded rangeland, its use has become controversial in the current management set...

  8. Familiar and unfamiliar face recognition in crested macaques (Macaca nigra)

    PubMed Central

    Micheletta, Jérôme; Whitehouse, Jamie; Parr, Lisa A.; Marshman, Paul; Engelhardt, Antje; Waller, Bridget M.

    2015-01-01

    Many species use facial features to identify conspecifics, which is necessary to navigate a complex social environment. The fundamental mechanisms underlying face processing are starting to be well understood in a variety of primate species. However, most studies focus on a limited subset of species tested with unfamiliar faces. As well as limiting our understanding of how widely distributed across species these skills are, this also limits our understanding of how primates process faces of individuals they know, and whether social factors (e.g. dominance and social bonds) influence how readily they recognize others. In this study, socially housed crested macaques voluntarily participated in a series of computerized matching-to-sample tasks investigating their ability to discriminate (i) unfamiliar individuals and (ii) members of their own social group. The macaques performed above chance on all tasks. Familiar faces were not easier to discriminate than unfamiliar faces. However, the subjects were better at discriminating higher ranking familiar individuals, but not unfamiliar ones. This suggests that our subjects applied their knowledge of their dominance hierarchies to the pictorial representation of their group mates. Faces of high-ranking individuals garner more social attention, and therefore might be more deeply encoded than other individuals. Our results extend the study of face recognition to a novel species, and consequently provide valuable data for future comparative studies. PMID:26064665

  9. cKit+ cardiac progenitors of neural crest origin

    PubMed Central

    Hatzistergos, Konstantinos E.; Takeuchi, Lauro M.; Saur, Dieter; Seidler, Barbara; Dymecki, Susan M.; Mai, Jia Jia; White, Ian A.; Balkan, Wayne; Kanashiro-Takeuchi, Rosemeire M.; Schally, Andrew V.; Hare, Joshua M.

    2015-01-01

    The degree to which cKit-expressing progenitors generate cardiomyocytes in the heart is controversial. Genetic fate-mapping studies suggest minimal contribution; however, whether or not minimal contribution reflects minimal cardiomyogenic capacity is unclear because the embryonic origin and role in cardiogenesis of these progenitors remain elusive. Using high-resolution genetic fate-mapping approaches with cKitCreERT2/+ and Wnt1::Flpe mouse lines, we show that cKit delineates cardiac neural crest progenitors (CNCkit). CNCkit possess full cardiomyogenic capacity and contribute to all CNC derivatives, including cardiac conduction system cells. Furthermore, by modeling cardiogenesis in cKitCreERT2-induced pluripotent stem cells, we show that, paradoxically, the cardiogenic fate of CNCkit is regulated by bone morphogenetic protein antagonism, a signaling pathway activated transiently during establishment of the cardiac crescent, and extinguished from the heart before CNC invasion. Together, these findings elucidate the origin of cKit+ cardiac progenitors and suggest that a nonpermissive cardiac milieu, rather than minimal cardiomyogenic capacity, controls the degree of CNCkit contribution to myocardium. PMID:26438843

  10. Chemokine-Mediated Migration of Mesencephalic Neural Crest Cells

    PubMed Central

    Rezzoug, Francine; Seelan, Ratnam S.; Bhattacherjee, Vasker; Greene, Robert M.; Pisano, M. Michele

    2011-01-01

    Clefts of the lip and/or palate are among the most prevalent birth defects affecting approximately 7000 newborns in the United States annually. Disruption of the developmentally programmed migration of neural crest cells (NCCs) into the orofacial region is thought to be one of the major causes of orofacial clefting. Signaling of the chemokine SDF-1 (Stromal Derived Factor-1) through its specific receptor, CXCR4, is required for the migration of many stem cell and progenitor cell populations from their respective sites of emergence to the regions where they differentiate into complex cell types, tissues and organs. In the present study, “transwell” assays of chick embryo mesencephalic (cranial) NCC migration and ex ovo whole embryo “bead implantation” assays were utilized to determine whether SDF-1/CXCR4 signaling mediates mesencephalic NCC migration. Results from this study demonstrate that attenuation of SDF-1 signaling, through the use of specific CXCR4 antagonists (AMD3100 and TN14003), disrupts the migration of mesencephalic NCCs into the orofacial region, suggesting a novel role for SDF-1/CXCR4 signaling in the directed migration of mesencephalic NCCs in the early stage embryo. PMID:22015108

  11. The flavonoids hesperidin and rutin promote neural crest cell survival.

    PubMed

    Nones, Jader; Costa, Ana Paula; Leal, Rodrigo Bainy; Gomes, Flávia Carvalho Alcantara; Trentin, Andréa Gonçalves

    2012-11-01

    The neural crest (NC) corresponds to a collection of multipotent and oligopotent progenitors endowed with both neural and mesenchymal potentials. The derivatives of the NC at trunk level include neurons and glial cells of the peripheral nervous system in addition to melanocytes, smooth muscle cells and some endocrine cells. Environmental factors control the fate decisions of NC cells. Despite the well-known influence of flavonoids on the central nervous system, the issue of whether they also influence NC cells has not been yet addressed. Flavonoids are polyphenolic compounds that are integral components of the human diet. The biological activities of these compounds cover a very broad spectrum, from anticancer and antibacterial activities to inhibition of bone reabsorption and modulation of inflammatory response. In the present work, we have investigated the actions of the flavonoids hesperidin, rutin and quercetin on NC cells of quail, in vitro. We show for the first time, that hesperidin and rutin increase the viability of trunk NC cells in culture, without affecting cell differentiation and proliferation. The molecular mechanism of this action is dependent on ERK2 and PI3K pathways. Quercetin had no effect on NC progenitors. Taken together, these results suggest that flavonoids hesperidin and rutin increase NC cell survival, which may be useful against the toxicity of some chemicals during embryonic development. PMID:22855262

  12. Generating trunk neural crest from human pluripotent stem cells

    PubMed Central

    Huang, Miller; Miller, Matthew L.; McHenry, Lauren K.; Zheng, Tina; Zhen, Qiqi; Ilkhanizadeh, Shirin; Conklin, Bruce R.; Bronner, Marianne E.; Weiss, William A.

    2016-01-01

    Neural crest cells (NCC) are stem cells that generate different lineages, including neuroendocrine, melanocytic, cartilage, and bone. The differentiation potential of NCC varies according to the level from which cells emerge along the neural tube. For example, only anterior “cranial” NCC form craniofacial bone, whereas solely posterior “trunk” NCC contribute to sympathoadrenal cells. Importantly, the isolation of human fetal NCC carries ethical and scientific challenges, as NCC induction typically occur before pregnancy is detectable. As a result, current knowledge of NCC biology derives primarily from non-human organisms. Important differences between human and non-human NCC, such as expression of HNK1 in human but not mouse NCC, suggest a need to study human NCC directly. Here, we demonstrate that current protocols to differentiate human pluripotent stem cells (PSC) to NCC are biased toward cranial NCC. Addition of retinoic acid drove trunk-related markers and HOX genes characteristic of a posterior identity. Subsequent treatment with bone morphogenetic proteins (BMPs) enhanced differentiation to sympathoadrenal cells. Our approach provides methodology for detailed studies of human NCC, and clarifies roles for retinoids and BMPs in the differentiation of human PSC to trunk NCC and to sympathoadrenal lineages. PMID:26812940

  13. Genes regulated by Kctd15 in the developing neural crest

    PubMed Central

    Wong, Thomas Chi Bun; Rebbert, Martha; Wang, Chengdong; Chen, Xiongfong; Heffer, Alison; Zarelli, Valeria E.; Dawid, Igor B.; Zhao, Hui

    2016-01-01

    Neural crest (NC) development is controlled precisely by a regulatory network with multiple signaling pathways and the involvement of many genes. The integration and coordination of these factors are still incompletely understood. Overexpression of Wnt3a and the BMP antagonist Chordin in animal cap cells from Xenopus blastulae induces a large number of NC specific genes. We previously suggested that Potassium Channel Tetramerization Domain containing 15 (Kctd15) regulates NC formation by affecting Wnt signaling and the activity of transcription factor AP-2. In order to advance understanding of the function of Kctd15 during NC development, we performed DNA microarray assays in explants injected with Wnt3a and Chordin, and identify genes that are affected by overexpression of Kctd15. Among many genes identified we chose Duf domain containing protein 1(ddcp1), Platelet-Derived Growth Factor Receptor a (pdgfra), Complement factor properdin (cfp), Zinc Finger SWIM-Type Containing 5 (zswim5), and complement component 3 (C3) to examine their expression by whole mount in situ hybridization. Our work points to a possible role for Kctd15 in the regulation of NC formation and other steps in embryonic development. PMID:27389986

  14. Design of the Carotid Revascularization Endarterectomy vs. Stenting Trial (CREST)

    PubMed Central

    Sheffet, Alice J.; Roubin, Gary; Howard, George; Howard, Virginia; Moore, Wesley; Meschia, James F.; Hobson, Robert W.; Brott, Thomas G.

    2009-01-01

    Rationale Carotid endarterectomy (CEA) and medical therapy were shown superior to medical therapy alone for symptomatic (≥50%) and asymptomatic (≥60%) stenosis. Carotid angioplasty stenting (CAS) offers a less invasive alternative. Establishing safety, efficacy, and durability of CAS requires rigorous comparison with CEA in symptomatic and asymptomatic patients. Aims The objective is to compare the efficacy of CAS versus CEA in patients with symptomatic (≥50%) or asymptomatic (≥60%) extracranial carotid stenosis. Design The Carotid Revascularization Endarterectomy vs. Stenting Trial (CREST) is a prospective, randomized, parallel, two-arm, multi-center trial with blinded endpoint adjudication. Primary endpoints are analyzed using standard time-to-event statistical modeling with adjustment for major baseline covariates. Primary analysis is on an intent-to-treat basis. Study Outcomes The primary outcome is the occurrence of any stroke, myocardial infarction, or death during a 30-day peri-procedural period, and ipsilateral stroke during follow-up of up to four years. Secondary outcomes include restenosis and health-related quality of life. PMID:20088993

  15. Premigratory and migratory neural crest cells are multipotent in vivo.

    PubMed

    Baggiolini, Arianna; Varum, Sandra; Mateos, José María; Bettosini, Damiano; John, Nessy; Bonalli, Mario; Ziegler, Urs; Dimou, Leda; Clevers, Hans; Furrer, Reinhard; Sommer, Lukas

    2015-03-01

    The neural crest (NC) is an embryonic stem/progenitor cell population that generates a diverse array of cell lineages, including peripheral neurons, myelinating Schwann cells, and melanocytes, among others. However, there is a long-standing controversy as to whether this broad developmental perspective reflects in vivo multipotency of individual NC cells or whether the NC is comprised of a heterogeneous mixture of lineage-restricted progenitors. Here, we resolve this controversy by performing in vivo fate mapping of single trunk NC cells both at premigratory and migratory stages using the R26R-Confetti mouse model. By combining quantitative clonal analyses with definitive markers of differentiation, we demonstrate that the vast majority of individual NC cells are multipotent, with only few clones contributing to single derivatives. Intriguingly, multipotency is maintained in migratory NC cells. Thus, our findings provide definitive evidence for the in vivo multipotency of both premigratory and migrating NC cells in the mouse. PMID:25748934

  16. Adrenergic innervation of the developing chick heart: neural crest ablations to produce sympathetically aneural hearts

    SciTech Connect

    Kirby, M.; Stewart, D.

    1984-11-01

    Ablation of various regions of premigratory trunk neural crest which gives rise to the sympathetic trunks was used to remove sympathetic cardiac innervation. Neuronal uptake of (/sup 3/H)-norepinephrine was used as an index of neuronal development in the chick atrium. Following ablation of neural crest over somites 10-15 or 15-20, uptake was significantly decreased in the atrium at 16 and 17 days of development. Ablation of neural crest over somites 5-10 and 20-25 caused no decrease in (/sup 3/H)-norepinephrine uptake. Removal of neural crest over somites 5-25 or 10-20 caused approximately equal depletions of (/sup 3/H)-norepinephrine uptake in the atrium. Cardiac norepinephrine concentration was significantly depressed following ablation of neural crest over somites 5-25 but not over somites 10-20. Light-microscopic and histofluorescent preparations confirmed the absence of sympathetic trunks in the region of the normal origin of the sympathetic cardiac nerves following neural crest ablation over somites 10-20. The neural tube and dorsal root ganglia were damaged in the area of the neural-crest ablation; however, all of these structures were normal cranial and caudal to the lesioned area. Development of most of the embryos as well as the morphology of all of the hearts was normal following the lesion. These results indicate that it is possible to produce sympathetically aneural hearts by neural-crest ablation; however, sympathetic cardiac nerves account for an insignificant amount of cardiac norepinephrine.

  17. A PTK7/Ror2 Co-Receptor Complex Affects Xenopus Neural Crest Migration

    PubMed Central

    Berger, Hanna; Rollwitz, Erik; Borchers, Annette

    2015-01-01

    Neural crest cells are a highly migratory pluripotent cell population that generates a wide array of different cell types and failure in their migration can result in severe birth defects and malformation syndromes. Neural crest migration is controlled by various means including chemotaxis, repellent guidance cues and cell-cell interaction. Non-canonical Wnt PCP (planar cell polarity) signaling has previously been shown to control cell-contact mediated neural crest cell guidance. PTK7 (protein tyrosine kinase 7) is a transmembrane pseudokinase and a known regulator of Wnt/PCP signaling, which is expressed in Xenopus neural crest cells and required for their migration. PTK7 functions as a Wnt co-receptor; however, it remains unclear by which means PTK7 affects neural crest migration. Expressing fluorescently labeled proteins in Xenopus neural crest cells we find that PTK7 co-localizes with the Ror2 Wnt-receptor. Further, co-immunoprecipitation experiments demonstrate that PTK7 interacts with Ror2. The PTK7/Ror2 interaction is likely relevant for neural crest migration, because Ror2 expression can rescue the PTK7 loss of function migration defect. Live cell imaging of explanted neural crest cells shows that PTK7 loss of function affects the formation of cell protrusions as well as cell motility. Co-expression of Ror2 can rescue these defects. In vivo analysis demonstrates that a kinase dead Ror2 mutant cannot rescue PTK7 loss of function. Thus, our data suggest that Ror2 can substitute for PTK7 and that the signaling function of its kinase domain is required for this effect. PMID:26680417

  18. Elk3 is essential for the progression from progenitor to definitive neural crest cell.

    PubMed

    Rogers, Crystal D; Phillips, Jacquelyn L; Bronner, Marianne E

    2013-02-15

    Elk3/Net/Sap2 (here referred to as Elk3) is an Ets ternary complex transcriptional repressor known for its involvement in angiogenesis during embryonic development. Although Elk3 is expressed in various tissues, additional roles for the protein outside of vasculature development have yet to be reported. Here, we characterize the early spatiotemporal expression pattern of Elk3 in the avian embryo using whole mount in situ hybridization and quantitative RT-PCR and examine the effects of its loss of function on neural crest development. At early stages, Elk3 is expressed in the head folds, head mesenchyme, intersomitic vessels, and migratory cranial neural crest (NC) cells. Loss of the Elk3 protein results in the retention of Pax7+ precursors in the dorsal neural tube that fail to upregulate neural crest specifier genes, FoxD3, Sox10 and Snail2, resulting in embryos with severe migration defects. The results putatively place Elk3 downstream of neural plate border genes, but upstream of neural crest specifier genes in the neural crest gene regulatory network (NC-GRN), suggesting that it is critical for the progression from progenitor to definitive neural crest cell. PMID:23266330

  19. Requirement for Foxd3 in the maintenance of neural crest progenitors.

    PubMed

    Teng, Lu; Mundell, Nathan A; Frist, Audrey Y; Wang, Qiaohong; Labosky, Patricia A

    2008-05-01

    Understanding the molecular mechanisms of stem cell maintenance is crucial for the ultimate goal of manipulating stem cells for the treatment of disease. Foxd3 is required early in mouse embryogenesis; Foxd3(-/-) embryos fail around the time of implantation, cells of the inner cell mass cannot be maintained in vitro, and blastocyst-derived stem cell lines cannot be established. Here, we report that Foxd3 is required for maintenance of the multipotent mammalian neural crest. Using tissue-specific deletion of Foxd3 in the neural crest, we show that Foxd3(flox/-); Wnt1-Cre mice die perinatally with a catastrophic loss of neural crest-derived structures. Cranial neural crest tissues are either missing or severely reduced in size, the peripheral nervous system consists of reduced dorsal root ganglia and cranial nerves, and the entire gastrointestinal tract is devoid of neural crest derivatives. These results demonstrate a global role for this transcriptional repressor in all aspects of neural crest maintenance along the anterior-posterior axis, and establish an unprecedented molecular link between multiple divergent progenitor lineages of the mammalian embryo. PMID:18367558

  20. Convergent Evolution of Head Crests in Two Domesticated Columbids Is Associated with Different Missense Mutations in EphB2.

    PubMed

    Vickrey, Anna I; Domyan, Eric T; Horvath, Martin P; Shapiro, Michael D

    2015-10-01

    Head crests are important display structures in wild bird species and are also common in domesticated lineages. Many breeds of domestic rock pigeon (Columba livia) have crests of reversed occipital feathers, and this recessive trait is associated with a nonsynonymous coding mutation in the intracellular kinase domain of EphB2 (Ephrin receptor B2). The domestic ringneck dove (Streptopelia risoria) also has a recessive crested morph with reversed occipital feathers, and interspecific crosses between crested doves and pigeons produce crested offspring, suggesting a similar genetic basis for this trait in both species. We therefore investigated EphB2 as a candidate for the head crest phenotype of ringneck doves and identified a nonsynonymous coding mutation in the intracellular kinase domain that is significantly associated with the crested morph. This mutation is over 100 amino acid positions away from the crest mutation found in rock pigeons, yet both mutations are predicted to negatively affect the function of ATP-binding pocket. Furthermore, bacterial toxicity assays suggest that "crest" mutations in both species severely impact kinase activity. We conclude that head crests are associated with different mutations in the same functional domain of the same gene in two different columbid species, thereby representing striking evolutionary convergence in morphology and molecules. PMID:26104009

  1. Facial expression recognition in crested macaques (Macaca nigra).

    PubMed

    Micheletta, Jérôme; Whitehouse, Jamie; Parr, Lisa A; Waller, Bridget M

    2015-07-01

    Facial expressions are a main communication channel used by many different species of primate. Despite this, we know relatively little about how primates discriminate between different facial expressions, and most of what we do know comes from a restricted number of well-studied species. In this study, three crested macaques (Macaca nigra) took part in matching-to-sample tasks where they had to discriminate different facial expressions. In a first experiment, the macaques had to match a photograph of a facial expression to another exemplar of the same expression produced by a different individual, against examples of one of three other types of expressions and neutral faces. In a second experiment, they had to match a dynamic video recording of a facial expression to a still photograph of another exemplar of the same facial expression produced by another individual, also against one of four other expressions. The macaques performed above chance in both tasks, identifying expressions as belonging to the same category regardless of individual identity. Using matrix correlations and multidimensional scaling, we analysed the pattern of errors to see whether overall similarity between facial expressions and/or specific morphological features caused the macaques to confuse facial expressions. Overall similarity, measured with the macaque facial action coding system (maqFACS), did not correlate with performances. Instead, functional similarities between facial expressions could be responsible for the observed pattern of error. These results expand previous findings to a novel primate species and highlight the potential of using video stimuli to investigate the perception and categorisation of visual signals in primates. PMID:25821924

  2. Probing dark matter crests with white dwarfs and IMBHs

    NASA Astrophysics Data System (ADS)

    Amaro-Seoane, P.; Casanellas, J.; Schödel, R.; Davidson, E.; Cuadra, J.

    2016-06-01

    White dwarfs (WDs) are the most promising captors of dark matter (DM) particles in the crests that are expected to build up in the cores of dense stellar clusters. The DM particles could reach sufficient densities in WD cores to liberate energy through self-annihilation. The extinction associated with our Galactic Centre makes it impossible to detect the potential-associated luminosities, contrary to smaller stellar systems which are close enough to us and not heavily extincted, such as -Cen. We investigate the prospects of detection of DM-burning WDs in a stellar cluster harbouring an intermediate-mass black hole (IMBH), which leads to higher densities of DM at the centre. We calculate the capture rate and estimate the luminosity that a WD would emit depending on its distance to the centre of the cluster. Direct-summation N-body simulations of -Cen yield a non-negligible number of WDs in the range of radii of interest. We apply our assumption to published Hubble Space Telescope/Advanced Camera for Surveys observations of stars in the centre of -Cen and, although we are not able to identify any evident candidate, we proof that their bunching up at high luminosities would be unique. We predict that DM burning will lead to a truncation of the cooling sequence at the faint end. The detection of DM burning in future observations of dense stellar clusters could allow us to probe different models of DM distributions and characteristics. On the other hand, if DM-burning WDs really exist, their number and properties could give hints to the existence of IMBHs.

  3. Historical model for editor and Office of Research Integrity cooperation in handling allegations, investigation, and retraction in a contentious (Abbs) case of research misconduct.

    PubMed

    Price, Alan R; Daroff, Robert B

    2015-01-01

    Cooperation between a journal editor and the federal Office of Research Integrity (ORI) in addressing investigations of research misconduct, each performing their own responsibilities while keeping each other informed of events and evidence, can be critical to the professional and regulatory resolution of a case. This paper describes the history of one of ORI's most contentious investigations that involved falsification of research on Parkinson's disease patients by James Abbs, Professor of Neurology, University of Wisconsin, published in the journal Neurology, which was handled cooperatively by the authors, who were the chief ORI investigator and the Editor-in-Chief of Neurology, respectively. PMID:25397599

  4. Resolving time and space constraints during neural crest formation and delamination.

    PubMed

    Duband, Jean-Loup; Dady, Alwyn; Fleury, Vincent

    2015-01-01

    A striking feature of neural crest development in vertebrates is that all the specification, delamination, migration, and differentiation steps occur consecutively in distinct areas of the embryo and at different timings of development. The significance and consequences of this partition into clearly separated events are not fully understood yet, but it ought to be related to the necessity of controlling precisely and independently each step, given the wide array of cell types and tissues derived from the neural crest and the long duration of their development spanning almost the entire embryonic life. In this chapter, using the examples of early neural crest induction and delamination, we discuss how time and space constraints influence their development and describe the molecular and cellular responses that are employed by cells to adapt. In the first example, we analyze how cell sorting and cell movements cooperate to allow nascent neural crest cells, which are initially mingled with other neurectodermal progenitors after induction, to segregate from the neural tube and ectoderm populations and settle at the apex of the neural tube prior to migration. In the second example, we examine how cadherins drive the entire process of neural crest segregation from the rest of the neurectoderm by their dual role in mediating first cell sorting and cohesion during specification and later in promoting their delamination. In the third example, we describe how the expression and activity of the transcription factors known to drive epithelium-to-mesenchyme transition (EMT) are regulated timely and spatially by the cellular machinery so that they can alternatively and successively regulate neural crest specification and delamination. In the last example, we briefly tackle the problem of how factors triggering EMT may elicit different cell responses in neural tube and neural crest progenitors. PMID:25662257

  5. Fate of the mammalian cranial neural crest during tooth and mandibular morphogenesis.

    PubMed

    Chai, Y; Jiang, X; Ito, Y; Bringas, P; Han, J; Rowitch, D H; Soriano, P; McMahon, A P; Sucov, H M

    2000-04-01

    Neural crest cells are multipotential stem cells that contribute extensively to vertebrate development and give rise to various cell and tissue types. Determination of the fate of mammalian neural crest has been inhibited by the lack of appropriate markers. Here, we make use of a two-component genetic system for indelibly marking the progeny of the cranial neural crest during tooth and mandible development. In the first mouse line, Cre recombinase is expressed under the control of the Wnt1 promoter as a transgene. Significantly, Wnt1 transgene expression is limited to the migrating neural crest cells that are derived from the dorsal CNS. The second mouse line, the ROSA26 conditional reporter (R26R), serves as a substrate for the Cre-mediated recombination. Using this two-component genetic system, we have systematically followed the migration and differentiation of the cranial neural crest (CNC) cells from E9.5 to 6 weeks after birth. Our results demonstrate, for the first time, that CNC cells contribute to the formation of condensed dental mesenchyme, dental papilla, odontoblasts, dentine matrix, pulp, cementum, periodontal ligaments, chondrocytes in Meckel's cartilage, mandible, the articulating disc of temporomandibular joint and branchial arch nerve ganglia. More importantly, there is a dynamic distribution of CNC- and non-CNC-derived cells during tooth and mandibular morphogenesis. These results are a first step towards a comprehensive understanding of neural crest cell migration and differentiation during mammalian craniofacial development. Furthermore, this transgenic model also provides a new tool for cell lineage analysis and genetic manipulation of neural-crest-derived components in normal and abnormal embryogenesis. PMID:10725243

  6. Adult Palatum as a Novel Source of Neural Crest-Related Stem Cells

    PubMed Central

    Widera, Darius; Zander, Christin; Heidbreder, Meike; Kasperek, Yvonne; Noll, Thomas; Seitz, Oliver; Saldamli, Belma; Sudhoff, Holger; Sader, Robert; Kaltschmidt, Christian; Kaltschmidt, Barbara

    2009-01-01

    Somatic neural and neural crest stem cells are promising sources for cellular therapy of several neurodegenerative diseases. However, because of practical considerations such as inadequate accessibility of the source material, the application of neural crest stem cells is strictly limited. The secondary palate is a highly regenerative and heavily innervated tissue, which develops embryonically under direct contribution of neural crest cells. Here, we describe for the first time the presence of nestin-positive neural crest-related stem cells within Meissner corpuscles and Merkel cell-neurite complexes located in the hard palate of adult Wistar rats. After isolation, palatal neural crest-related stem cells (pNC-SCs) were cultivated in the presence of epidermal growth factor and fibroblast growth factor under serum-free conditions, resulting in large amounts of neurospheres. We used immunocytochemical techniques and reverse transcriptase-polymerase chain reaction to assess the expression profile of pNC-SCs. In addition to the expression of neural crest stem cell markers such as Nestin, Sox2, and p75, we detected the expression of Klf4, Oct4, and c-Myc. pNC-SCs differentiated efficiently into neuronal and glial cells. Finally, we investigated the potential expression of stemness markers within the human palate. We identified expression of stem cell markers nestin and CD133 and the transcription factors needed for reprogramming of somatic cells into pluripotent cells: Sox2, Oct4, Klf4, and c-Myc. These data show that cells isolated from palatal rugae form neurospheres, are highly plastic, and express neural crest stem cell markers. In addition, pNC-SCs may have the ability to differentiate into functional neurons and glial cells, serving as a starting point for therapeutic studies. Stem Cells 2009;27:1899–1910 PMID:19544446

  7. A statistical study of equatorial ionospheric anomaly single crest from SWARM satellite

    NASA Astrophysics Data System (ADS)

    Fathy, Adel; Ghamry, Essam

    2016-07-01

    However the, the Equatorial Ionospheric Anomaly (EIA) is being represented by two crests within ±15 degree in latitudes, a single crest is being observed in the entire ionosphere. A statistical study of 1351 EIA single crest for ionospheric electron density from SWARM-A satellite are investigated within the interval April 2014 to April 2015. Our analysis focused on local time, seasonal and both geographic and geomagnetic latitudinal variations in addition EIA amplitude with respect to solar and geomagnetic activities. Our results showed that the maximum number of EIA single crest events peak mainly in the dayside region around 1000-1200 LT. The electron density amplitude of the EIA single crest events in the dayside region jumps to 3 times its dawn and nightside amplitude. Spring events observed very close to the magnetic equator in comparison to other seasons. Their maximum number occurs within the magnetic equator, while their seasonal distribution showed that the majority of winter events located in the southern hemisphere, while spring events are centered around the magnetic equator. Regardless of local time or longitudinal location of summer events, it always has smaller amplitude in comparison with other seasons. Seasonal distribution showed that the average number of EIA single crests per month is approximately 200 events with relatively large number of events in September than March. Also it showed two maxima at spring and autumn, and two minima at summer and winter. The average magnetic latitude of summer events is +10 degrees in northern hemisphere. The majority of dawnside and nightside summer events is located in northern hemisphere and reverses its location in winter, while dayside and duskside events seem to be centered within the magnetic equator. The EIA solar and magnetic activity dependence showed that almost EIA single crest events occurred at low and moderate activity which is in partial agreement with previous studies and dayside events

  8. Persistent expression of Pax3 in the neural crest causes cleft palate and defective osteogenesis in mice

    PubMed Central

    Wu, Meilin; Li, Jun; Engleka, Kurt A.; Zhou, Bo; Lu, Min Min; Plotkin, Joshua B.; Epstein, Jonathan A.

    2008-01-01

    Transcription factors regulate tissue patterning and cell fate determination during development; however, expression of early regulators frequently abates upon differentiation, suggesting that they may also play a role in maintaining an undifferentiated phenotype. The transcription factor paired box 3 (Pax3) is expressed by multipotent neural crest precursors and is implicated in neural crest disorders in humans such as Waardenburg syndrome. Pax3 is required for development of multiple neural crest lineages and for activation of lineage-specific programs, yet expression is generally extinguished once neural crest cells migrate from the dorsal neural tube and differentiate. Using a murine Cre-inducible system, we asked whether persistent Pax3 expression in neural crest derivatives would affect development or patterning. We found that persistent expression of Pax3 in cranial neural crest cells resulted in cleft palate, ocular defects, malformation of the sphenoid bone, and perinatal lethality. Furthermore, we demonstrated that Pax3 directly regulates expression of Sostdc1, a soluble inhibitor of bone morphogenetic protein (BMP) signaling. Persistent Pax3 expression renders the cranial crest resistant to BMP-induced osteogenesis. Thus, one mechanism by which Pax3 maintains the undifferentiated state of neural crest mesenchyme may be to block responsiveness to differentiation signals from the environment. These studies provide in vivo evidence for the importance of Pax3 downregulation during differentiation of multipotent neural crest precursors and cranial development. PMID:18483623

  9. A field study of "lambda distribution" for breaking wave crests

    NASA Astrophysics Data System (ADS)

    Dulov, V.; Mironov, A.

    2009-04-01

    "Lambda distribution" concept introduced by Phillips (1985) provides a way to link wind wave spectra and numerous important measures of the air-sea interface processes related to wave breaking. Production of sea drops in the near water atmospheric layer (Kudryavtsev, 2006), radar backscattering due to wave breaking (Phillips, 1988, Kudryavtsev et al., 2003), turbulent mixing in the uppermost sea layer (Kudryavtsev et al., 2008) and other phenomena were recently studied on the basis of this approach. In this connection experimental investigations of the key theoretical quantity, Λ(c)dc, the average length of breaking crests per unit area propagating with speeds in the range (c, c + dc), and its dependence on wave spectra are of obvious importance. An experimental study of Λ(c) was performed during three field campaigns (2003, 2005 and 2008) on the Black Sea research platform of Marine Hydrophysical Institute (National Academy of Sciences of Ukraine). Simultaneous recordings of wave breaking measures (with video camera) and wave 2D-spectra (with an array of resistance wave staffs) were obtained under variety of wave conditions at wind speed 4-20m/s. A special method was developed to evaluate geometrical and kinematical whitecap parameters including their vectors of advance velocity. Individual whitecaps corresponding to active phase of wave breaking (phase A) were extracted from video recordings of the sea surface practically without human influence on the process of data processing because the method is based on physical considerations of sea surface brightness and empirical information on whitecap dynamics. Estimations of Λ(c) were derived from data obtained. Spectral energy dissipation rates were evaluated from the wave spectra and from the Λ(c) in accordance with Phillips approach (1985). Their comparison for every experimental run exhibits poor agreement, but a good agreement was found for integral dissipation rates for all data. Value of Phillips theory

  10. Corresponding Mitochondrial DNA and Niche Divergence for Crested Newt Candidate Species

    PubMed Central

    Wielstra, Ben; Beukema, Wouter; Arntzen, Jan W.; Skidmore, Andrew K.; Toxopeus, Albertus G.; Raes, Niels

    2012-01-01

    Genetic divergence of mitochondrial DNA does not necessarily correspond to reproductive isolation. However, if mitochondrial DNA lineages occupy separate segments of environmental space, this supports the notion of their evolutionary independence. We explore niche differentiation among three candidate species of crested newt (characterized by distinct mitochondrial DNA lineages) and interpret the results in the light of differences observed for recognized crested newt species. We quantify niche differences among all crested newt (candidate) species and test hypotheses regarding niche evolution, employing two ordination techniques (PCA-env and ENFA). Niche equivalency is rejected: all (candidate) species are found to occupy significantly different segments of environmental space. Furthermore, niche overlap values for the three candidate species are not significantly higher than those for the recognized species. As the three candidate crested newt species are, not only in terms of mitochondrial DNA genetic divergence, but also ecologically speaking, as diverged as the recognized crested newt species, our findings are in line with the hypothesis that they represent cryptic species. We address potential pitfalls of our methodology. PMID:23029564

  11. Double crests of peak height in the equatorial ionospheric F2 layer observed by COSMIC

    NASA Astrophysics Data System (ADS)

    Luan, Xiaoli; Lei, Jiuhou; Dou, Xiankang; Dang, Tong

    2016-01-01

    For the first time, we report daytime double crests of peak height (hmF2) in the F2 layer based on the Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC) observations during 2007-2014. Evident double crests of hmF2 occurred at around ±10° geomagnetic latitude with a trough over the magnetic equator at low solar activity and at March equinox. This phenomenon is referred to as an equatorial height anomaly (EHA) of the ionospheric F2 layer. The double crests became less obvious at September equinox and disappeared at solstices. At solstices only one crest was observed in the summer hemisphere, which is probably associated with transequatorial neutral winds. In addition, the double EHA crests generally take place during 10:00-14:00 local times. Our results indicate that the EHA favors the conditions of strong vertical plasma drifts and weak transequatorial neutral winds during low solar activity. The EHA feature is reproduced by the Thermosphere Ionosphere Electrodynamics Global Circulation Model at March equinox and low solar activity.

  12. Dissecting early regulatory relationships in the lamprey neural crest gene network.

    PubMed

    Nikitina, Natalya; Sauka-Spengler, Tatjana; Bronner-Fraser, Marianne

    2008-12-23

    The neural crest, a multipotent embryonic cell type, originates at the border between neural and nonneural ectoderm. After neural tube closure, these cells undergo an epithelial-mesenchymal transition, migrate to precise, often distant locations, and differentiate into diverse derivatives. Analyses of expression and function of signaling and transcription factors in higher vertebrates has led to the proposal that a neural crest gene regulatory network (NC-GRN) orchestrates neural crest formation. Here, we interrogate the NC-GRN in the lamprey, taking advantage of its slow development and basal phylogenetic position to resolve early inductive events, 1 regulatory step at the time. To establish regulatory relationships at the neural plate border, we assess relative expression of 6 neural crest network genes and effects of individually perturbing each on the remaining 5. The results refine an upstream portion of the NC-GRN and reveal unexpected order and linkages therein; e.g., lamprey AP-2 appears to function early as a neural plate border rather than a neural crest specifier and in a pathway linked to MsxA but independent of ZicA. These findings provide an ancestral framework for performing comparative tests in higher vertebrates in which network linkages may be more difficult to resolve because of their rapid development. PMID:19104059

  13. Dissecting early regulatory relationships in the lamprey neural crest gene network

    PubMed Central

    Nikitina, Natalya; Sauka-Spengler, Tatjana; Bronner-Fraser, Marianne

    2008-01-01

    The neural crest, a multipotent embryonic cell type, originates at the border between neural and nonneural ectoderm. After neural tube closure, these cells undergo an epithelial–mesenchymal transition, migrate to precise, often distant locations, and differentiate into diverse derivatives. Analyses of expression and function of signaling and transcription factors in higher vertebrates has led to the proposal that a neural crest gene regulatory network (NC-GRN) orchestrates neural crest formation. Here, we interrogate the NC-GRN in the lamprey, taking advantage of its slow development and basal phylogenetic position to resolve early inductive events, 1 regulatory step at the time. To establish regulatory relationships at the neural plate border, we assess relative expression of 6 neural crest network genes and effects of individually perturbing each on the remaining 5. The results refine an upstream portion of the NC-GRN and reveal unexpected order and linkages therein; e.g., lamprey AP-2 appears to function early as a neural plate border rather than a neural crest specifier and in a pathway linked to MsxA but independent of ZicA. These findings provide an ancestral framework for performing comparative tests in higher vertebrates in which network linkages may be more difficult to resolve because of their rapid development. PMID:19104059

  14. Mesodermal expression of integrin α5β1 regulates neural crest development and cardiovascular morphogenesis

    PubMed Central

    Liang, Dong; Wang, Xia; Mittal, Ashok; Dhiman, Sonam; Hou, Shuan-Yu; Degenhardt, Karl; Astrof, Sophie

    2014-01-01

    Integrin α5-null embryos die in mid-gestation from severe defects in cardiovascular morphogenesis, which stem from defective development of the neural crest, heart and vasculature. To investigate the role of integrin α5β1 in cardiovascular development, we used the Mesp1Cre knock-in strain of mice to ablate integrin α5 in the anterior mesoderm, which gives rise to all of the cardiac and many of the vascular and muscle lineages in the anterior portion of the embryo. Surprisingly, we found that mutant embryos displayed numerous defects related to the abnormal development of the neural crest such as cleft palate, ventricular septal defect, abnormal development of hypoglossal nerves, and defective remodeling of the aortic arch arteries. We found that defects in arch artery remodeling stem from the role of mesodermal integrin α5β1 in neural crest proliferation and differentiation into vascular smooth muscle cells, while proliferation of pharyngeal mesoderm and differentiation of mesodermal derivatives into vascular smooth muscle cells was not defective. Taken together our studies demonstrate a requisite role for mesodermal integrin α5β1 in signaling between the mesoderm and the neural crest, thereby regulating neural crest-dependent morphogenesis of essential embryonic structures. PMID:25242040

  15. Local increase level of chondroitin sulfate induces changes in the rhombencephalic neural crest migration.

    PubMed

    Moro Balbás, J A; Gato, A; Alonso, M; Barbosa, E

    1998-03-01

    Numerous studies suggest that chondroitin sulfate proteoglycan (CSPG) inhibits neural crest cells (NCC) migration at the trunk level. However, its action on the cephalic neural crest is not clear. To determine this action, we have microinjected 0.5 nl of different concentrations of chondroitin sulfate (CS) at the anterior rhombencephalon level in 9 stage chick embryos, as well as subgerminally administering beta-D-xyloside to 8 stage chick embryos. Beta-D-xyloside disrupts CSPG synthesis, producing an increase in CS free chains in several embryonal anlages. Chondroitin sulfate microinjected embryos and beta-D xyloside treated embryos were reincubated until attaining 12 stage. Results obtained for both experimental groups were similar. Immunoreactivity with HNK-1 antibody revealed that NCC did not migrate, remaining near the rhombencephalon dorsal wall; in addition, several NCC did not separate from the neural fold, becoming invaginated towards the rhombencephalon cavity. Our findings indicate that an increase in CS free chains in cephalic neural crest migratory routes not only disrupts their migration, but also impedes delamination and detachment of the rhombencephalic neuroepithelium NCC. These data suggest that the inhibitory action upon the neural crest migration attributed to CSPG may rest on its glycosaminoglycan (GAG). We cannot, however, rule out the possibility that increases in other GAGs apart from CS, may produce similar effects on neural crest migration. PMID:9551866

  16. EWS-FLI1 causes neuroepithelial defects and abrogates emigration of neural crest stem cells.

    PubMed

    Coles, Edward G; Lawlor, Elizabeth R; Bronner-Fraser, Marianne

    2008-09-01

    The most frequently occurring chromosomal translocation that gives rise to the Ewing's sarcoma family of tumors (ESFT) is the chimeric fusion gene EWS-FLI1 that encodes an oncogenic protein composed of the N terminus of EWS and the C terminus of FLI1. Although the genetic basis of ESFT is fairly well understood, its putative cellular origin remains to be determined. Previous work has proposed that neural crest progenitor cells may be the causative cell type responsible for ESFT. However, surprisingly little is known about the expression pattern or role of either wild-type EWS or wild-type FLI1 in this cell population during early embryonic development. Using the developing chick embryo as a model system, we identified EWS expression in emigrating and migratory neural crest stem cells, whereas FLI1 transcripts were found to be absent in these populations and were restricted to developing endothelial cells. By ectopically expressing EWS-FLI1 or wild-type FLI1 in the developing embryo, we have been able to study the cellular transformations that ensue in the context of an in vivo model system. Our results reveal that misexpression of the chimeric EWS-FLI1 fusion gene, or wild-type FLI1, in the developing neural crest stem cell population leads to significant aberrations in neural crest development. An intriguing possibility is that misexpression of the EWS-FLI1 oncogene in neural crest-derived stem cells may be an initiating event in ESFT genesis. PMID:18556509

  17. A study on ionospheric scintillation near the EIA crest in relation to equatorial electrodynamics

    NASA Astrophysics Data System (ADS)

    Chatterjee, S.; Chakraborty, S. K.; Veenadhari, B.; Banola, S.

    2014-02-01

    Equatorial electrojet (EEJ) data, which are considered as a proxy index of equatorial electric field, are analyzed in conjunction with equatorial ionosonde, total electron content (TEC) and scintillation data near the equatorial ionization anomaly (EIA) crest for the equinoctial months of high solar activity years (2011-2012) to identify any precursor index of postsunset evolution of equatorial electron density irregularities and subsequent occurrence of scintillation near the northern EIA crest. Only geomagnetically quiet and normal electrojet days are considered. The diurnal profiles of EEJ on the scintillation days exhibit a secondary enhancement in the afternoon to presunset hours following diurnal peaks. A series of electrodynamical processes conducive for generation of irregularities emerge following secondary enhancement of EEJ. Latitudinal profile of TEC exhibits resurgence in EIA structure around the postsunset period. Diurnal TEC profile near the EIA crest resembles postsunset secondary enhancement on the days with afternoon enhancement in EEJ. Occurrence of equatorial spread F and postsunset scintillation near the EIA crest seems to follow the secondary enhancement events in EEJ. Both the magnitude and duration of enhanced EEJ are found to be important for postsunset intensification of EIA structure and subsequent occurrence of equatorial irregularities. A critical value combining the two may be considered an important precursor for postsunset occurrence of scintillation near the EIA crest. The results are validated using archived data for the years 1989-1990 and explained in terms of modulation effects of enhanced equatorial fountain.

  18. [Progress in the study of syndromic hearing loss resulted from neural crest abnormalities].

    PubMed

    Yalan, Liu; Hua, Zhang; Yong, Feng

    2014-11-01

    More than 400 types of syndromic hearing loss (SHL) have been reported so far, in which Waardenburg syndrome (WS), congenital microtia syndrome (CMS), and large vestibular aqueduct syndrome (LVAS) are the most common ones in clinic. However, it is difficult to study the genetic basis and pathogenesis of SHL in a systematical way because of the strong clinical and genetic heterogeneity of SHL. Dysfunction of neural crest cells (NCC), which are caused by the gene interaction network extended from SOX10 and PAX3, are relevant to the phenotype of WS, CMS and LVAS. Our previous study also confirmed that the gene network was involved in the pathogenesis of WS. In this review, we summarize research progress in the pathogenic mechanisms of SHL resulted from defects in neural crest decelopment, and provide the gene interaction network of neural crest abnormalities resulting in SHL, and hope to provide research ideas and theoretical basis for the systematical study on pathogenesis of common SHL. PMID:25567871

  19. Analysis on damage to TF coils of a compact reversed shear tokamak CREST

    NASA Astrophysics Data System (ADS)

    Huang, Q.; Zheng, S.; Lu, L.; Zeng, Q.; Hiwatari, R.; Asaoka, Y.; Okano, K.; Ogawa, Y.

    2007-08-01

    CREST is a conceptual tokamak reactor design with high β plasma, high thermal efficiency, competitive cost and water-cooled ferritic steel components. Some of its parameters are similar to those of the ITER advanced mode plasma. In this manuscript, the specific issues and analysis on damage to TF coils of CREST were carried out based on the three-dimensional model of the CREST with the widely used code MCNP/4C and the IAEA latest released FENDL/2.1 data library. Damage to some specific regions of the TF coils near large openings and at the inboard mid-plane are calculated and analyzed. Parameters such as the distributions of nuclear heat density, fast neutron flux, dose rate to the epoxy insulator, and peak displacement dose to Cu conductor for the TF coil near these regions were calculated and analyzed. The shield thicknesses at these regions are optimized.

  20. Elongator Protein 3 (Elp3) stabilizes Snail1 and regulates neural crest migration in Xenopus

    PubMed Central

    Yang, Xiangcai; Li, Jiejing; Zeng, Wanli; Li, Chaocui; Mao, Bingyu

    2016-01-01

    Elongator protein 3 (Elp3) is the enzymatic unit of the elongator protein complex, a histone acetyltransferase complex involved in transcriptional elongation. It has long been shown to play an important role in cell migration; however, the underlying mechanism is unknown. Here, we showed that Elp3 is expressed in pre-migratory and migrating neural crest cells in Xenopus embryos, and knockdown of Elp3 inhibited neural crest cell migration. Interestingly, Elp3 binds Snail1 through its zinc-finger domain and inhibits its ubiquitination by β-Trcp without interfering with the Snail1/Trcp interaction. We showed evidence that Elp3-mediated stabilization of Snail1 was likely involved in the activation of N-cadherin in neural crest cells to regulate their migratory ability. Our findings provide a new mechanism for the function of Elp3 in cell migration through stabilizing Snail1, a master regulator of cell motility. PMID:27189455

  1. Radionuclide diagnosis and therapy of neural crest tumors using iodine-131 metaiodobenzylguanidine

    SciTech Connect

    Hoefnagel, C.A.; Voute, P.A.; de Kraker, J.; Marcuse, H.R.

    1987-03-01

    The successful application of (/sup 131/I)metaiodobenzylguanidine (MIBG) in diagnosis and therapy of pheochromocytoma has led to its use in other tumors which derive from the neural crest and potentially concentrate this radiopharmaceutical as well. In the present series, (/sup 131/)MIBG total-body scintigraphy was used for detection of neuroblastoma in 47 patients and 47 cases of other neural crest tumors. The method was found to be as reliable in neuroblastoma (sensitivity 95%, specificity 100%), as it is in pheochromocytoma. Although other neural crest tumors may concentrate (/sup 131/I)MIBG, this is not a consistent finding; however, it is useful to investigate which tumors do, as this may provide an alternative treatment modality for some patients. Although followup is still very short, preliminary results of therapeutic use of (/sup 131/I) MIBG in 21 patients indicate that this treatment modality may be effective in neuroblastoma and malignant pheochromocytoma.

  2. Solar Simulation for the CREST Preflight Thermal-Vacuum Test at B-2

    NASA Technical Reports Server (NTRS)

    Ziemke, Robert A.

    2013-01-01

    In June 2011, the multi-university sponsored Cosmic Ray Electron Synchrotron Telescope (CREST) has undergone thermal-vacuum qualification testing at the NASA Glenn Research Center (GRC), Plum Brook Station, Sandusky, Ohio. The testing was performed in the B- 2 Space Propulsion Facility vacuum chamber. The CREST was later flown over the Antarctic region as the payload of a stratospheric balloon. Solar simulation was provided by a system of planar infrared lamp arrays specifically designed for CREST. The lamp arrays, in conjunction with a liquid-nitrogen-cooled cryoshroud, achieved the required thermal conditions for the qualification tests. This report focuses on the design and analysis of the planar arrays based on first principles. Computational spreadsheets are included in the report.

  3. The Hippo pathway member YAP enhances human neural crest cell fate and migration

    PubMed Central

    Hindley, Christopher J.; Condurat, Alexandra Larisa; Menon, Vishal; Thomas, Ria; Azmitia, Luis M.; Davis, Jason A.; Pruszak, Jan

    2016-01-01

    The Hippo/YAP pathway serves as a major integrator of cell surface-mediated signals and regulates key processes during development and tumorigenesis. The neural crest is an embryonic tissue known to respond to multiple environmental cues in order to acquire appropriate cell fate and migration properties. Using multiple in vitro models of human neural development (pluripotent stem cell-derived neural stem cells; LUHMES, NTERA2 and SH-SY5Y cell lines), we investigated the role of Hippo/YAP signaling in neural differentiation and neural crest development. We report that the activity of YAP promotes an early neural crest phenotype and migration, and provide the first evidence for an interaction between Hippo/YAP and retinoic acid signaling in this system. PMID:26980066

  4. The Hippo pathway member YAP enhances human neural crest cell fate and migration.

    PubMed

    Hindley, Christopher J; Condurat, Alexandra Larisa; Menon, Vishal; Thomas, Ria; Azmitia, Luis M; Davis, Jason A; Pruszak, Jan

    2016-01-01

    The Hippo/YAP pathway serves as a major integrator of cell surface-mediated signals and regulates key processes during development and tumorigenesis. The neural crest is an embryonic tissue known to respond to multiple environmental cues in order to acquire appropriate cell fate and migration properties. Using multiple in vitro models of human neural development (pluripotent stem cell-derived neural stem cells; LUHMES, NTERA2 and SH-SY5Y cell lines), we investigated the role of Hippo/YAP signaling in neural differentiation and neural crest development. We report that the activity of YAP promotes an early neural crest phenotype and migration, and provide the first evidence for an interaction between Hippo/YAP and retinoic acid signaling in this system. PMID:26980066

  5. Unraveling the rapid radiation of crested newts (Triturus cristatus superspecies) using complete mitogenomic sequences

    PubMed Central

    2011-01-01

    Background The rapid radiation of crested newts (Triturus cristatus superspecies) comprises four morphotypes: 1) the T. karelinii group, 2) T. carnifex - T. macedonicus, 3) T. cristatus and 4) T. dobrogicus. These vary in body build and the number of rib-bearing pre-sacral vertebrae (NRBV). The phylogenetic relationships of the morphotypes have not yet been settled, despite several previous attempts, employing a variety of molecular markers. We here resolve the crested newt phylogeny by using complete mitochondrial genome sequences. Results Bayesian inference based on the mitogenomic data yields a fully bifurcating, significantly supported tree, though Maximum Likelihood inference yields low support values. The internal branches connecting the morphotypes are short relative to the terminal branches. Seen from the root of Triturus (NRBV = 13), a basal dichotomy separates the T. karelinii group (NRBV = 13) from the remaining crested newts. The next split divides the latter assortment into T. carnifex - T. macedonicus (NRBV = 14) versus T. cristatus (NRBV = 15) and T. dobrogicus (NRBV = 16 or 17). Conclusions We argue that the Bayesian full mitochondrial DNA phylogeny is superior to previous attempts aiming to recover the crested newt species tree. Furthermore, our new phylogeny involves a maximally parsimonious interpretation of NRBV evolution. Calibrating the phylogeny allows us to evaluate potential drivers for crested newt cladogenesis. The split between the T. karelinii group and the three other morphotypes, at ca. 10.4 Ma, is associated with the separation of the Balkan and Anatolian landmasses (12-9 Ma). No currently known vicariant events can be ascribed to the other two splits, first at ca. 9.3 Ma, separating T. carnifex - T. macedonicus, and second at ca. 8.8 Ma, splitting T. cristatus and T. dobrogicus. The crested newt morphotypes differ in the duration of their annual aquatic period. We speculate on the role that this ecological differentiation could have

  6. Evolution of neural crest and placodes: amphioxus as a model for the ancestral vertebrate?

    NASA Technical Reports Server (NTRS)

    Holland, L. Z.; Holland, N. D.

    2001-01-01

    Recent studies of protochordates (ascidian tunicates and amphioxus) have given insights into possible ancestors of 2 of the characteristic features of the vertebrate head: neural crest and placodes. The neural crest probably evolved from cells on either side of the neural plate-epidermis boundary in a protochordate ancestral to the vertebrates. In amphioxus, homologues of several vertebrate neural crest marker genes (BMP2/4, Pax3/7, Msx, Dll and Snail) are expressed at the edges of the neural plate and/or adjacent nonneural ectoderm. Some of these markers are also similarly expressed in tunicates. In protochordates, however, these cells, unlike vertebrate neural crest, neither migrate as individuals through embryonic tissues nor differentiate into a wide spectrum of cell types. Therefore, while the protochordate ancestor of the vertebrates probably had the beginnings of a genetic programme for neural crest formation, this programme was augmented in the earliest vertebrates to attain definitive neural crest. Clear homologues of vertebrate placodes are lacking in protochordates. However, both amphioxus and tunicates have ectodermal sensory cells. In tunicates these are all primary neurons, sending axons to the central nervous system, while in amphioxus, the ectodermal sensory cells include both primary neurons and secondary neurons lacking axons. Comparisons of developmental gene expression suggest that the anterior ectoderm in amphioxus may be homologous to the vertebrate olfactory placode, the only vertebrate placode with primary, not secondary, neurons. Similarly, biochemical, morphological and gene expression data suggest that amphioxus and tunicates also have homologues of the adenohypophysis, one of the few vertebrate structures derived from nonneurogenic placodes. In contrast, the origin of the other vertebrate placodes is very uncertain.

  7. CREST v2.1 Refined by a Distributed Linear Reservoir Routing Scheme

    NASA Astrophysics Data System (ADS)

    Shen, X.; Hong, Y.; Zhang, K.; Hao, Z.; Wang, D.

    2014-12-01

    Hydrologic modeling is important in water resources management, and flooding disaster warning and management. Routing scheme is among the most important components of a hydrologic model. In this study, we replace the lumped LRR (linear reservoir routing) scheme used in previous versions of the distributed hydrological model, CREST (coupled routing and excess storage) by a newly proposed distributed LRR method, which is theoretically more suitable for distributed hydrological models. Consequently, we have effectively solved the problems of: 1) low values of channel flow in daily simulation, 2) discontinuous flow value along the river network during flood events and 3) irrational model parameters. The CREST model equipped with both the routing schemes have been tested in the Gan River basin. The distributed LRR scheme has been confirmed to outperform the lumped counterpart by two comparisons, hydrograph validation and visual speculation of the continuity of stream flow along the river: 1) The CREST v2.1 (version 2.1) with the implementation of the distributed LRR achieved excellent result of [NSCE(Nash coefficient), CC (correlation coefficient), bias] =[0.897, 0.947 -1.57%] while the original CREST v2.0 produced only negative NSCE, close to zero CC and large bias. 2) CREST v2.1 produced more naturally smooth river flow pattern along the river network while v2.0 simulated bumping and discontinuous discharge along the mainstream. Moreover, we further observe that by using the distributed LRR method, 1) all model parameters fell within their reasonable region after an automatic optimization; 2) CREST forced by satellite-based precipitation and PET products produces a reasonably well result, i.e., (NSCE, CC, bias) = (0.756, 0.871, -0.669%) in the case study, although there is still room to improve regarding their low spatial resolution and underestimation of the heavy rainfall events in the satellite products.

  8. Reduced Dependence of Crested Ibis on Winter-Flooded Rice Fields: Implications for Their Conservation

    PubMed Central

    Sun, Yiwen; Skidmore, Andrew K.; Wang, Tiejun; van Gils, Hein A. M. J.; Wang, Qi; Qing, Baoping; Ding, Changqing

    2014-01-01

    The Crested Ibis Nipponia nippon was once thought to be extinct in the wild until seven birds were discovered in a remote mountain village in China in 1981. Studies suggested that winter-flooded rice fields play an essential role in nest site selection by the Crested Ibis and hence in their survival. Considerable efforts were therefore made to conserve the winter-flooded rice fields, but these have caused conflicts between the agricultural and conservation communities. The population and geographical range of the wild Crested Ibis has expanded greatly since 1981, but there is no spatial information on the winter-flooded rice fields, nor on the current association of nest sites and winter-flooded rice fields. We mapped winter-flooded rice fields across the entire current range of Crested Ibis using innovative remote sensing and geographical information systems (GIS) techniques. The spatial relationships between the nest site clusters and winter-flooded rice fields were quantified using Ward's hierarchical clustering method and Ripley's K-function. We show that both have significantly clumped distribution patterns and that they are positively associated. However, the dependence of Crested Ibis on the winter-flooded rice fields varied significantly among the nest site clusters and has decreased over the years, indicating the absence of winter-flooded rice fields is not constraining their recovery and population expansion. We therefore recommend that efforts should be made to protect the existing winter-flooded rice fields and to restore the functionality of natural and semi-natural wetlands, to encourage both in-situ conservation and the re-introduction of the Crested Ibis. In addition, we recommend that caution should be exercised when interpreting the habitat requirements of species with a narrow distribution, particularly when that interpretation is based only on their current habitat. PMID:24874870

  9. Williams Syndrome Transcription Factor is critical for neural crest cell function in Xenopus laevis

    PubMed Central

    Barnett, Chris; Yazgan, Oya; Kuo, Hui-Ching; Malakar, Sreepurna; Thomas, Trevor; Fitzgerald, Amanda; Harbour, Billy; Henry, Jonathan J.; Krebs, Jocelyn E.

    2012-01-01

    Williams Syndrome Transcription Factor (WSTF) is one of ~25 haplodeficient genes in patients with the complex developmental disorder Williams Syndrome (WS). WS results in visual/spatial processing defects, cognitive impairment, unique behavioral phenotypes, characteristic “elfin” facial features, low muscle tone and heart defects. WSTF exists in several chromatin remodeling complexes and has roles in transcription, replication, and repair. Chromatin remodeling is essential during embryogenesis, but WSTF’s role in vertebrate development is poorly characterized. To investigate the developmental role of WSTF, we knocked down WSTF in Xenopus laevis embryos using a morpholino that targets WSTF mRNA. BMP4 shows markedly increased and spatially aberrant expression in WSTF-deficient embryos, while SHH, MRF4, PAX2, EPHA4 and SOX2 expression are severely reduced, coupled with defects in a number of developing embryonic structures and organs. WSTF-deficient embryos display defects in anterior neural development. Induction of the neural crest, measured by expression of the neural crest-specific genes SNAIL and SLUG, is unaffected by WSTF depletion. However, at subsequent stages WSTF knockdown results in a severe defect in neural crest migration and/or maintenance. Consistent with a maintenance defect, WSTF knockdowns display a specific pattern of increased apoptosis at the tailbud stage in regions corresponding to the path of cranial neural crest migration. Our work is the first to describe a role for WSTF in proper neural crest function, and suggests that neural crest defects resulting from WSTF haploinsufficiency may be a major contributor to the pathoembryology of WS. PMID:22691402

  10. Isolation and characterization of eight novel microsatellite loci in the double-crested cormorant (Phalacrocorax auritus)

    USGS Publications Warehouse

    Mercer, Dacey; Haig, Susan; Mullins, Thomas

    2010-01-01

    We describe the isolation and characterization of eight microsatellite loci from the double-crested cormorant (Phalacrocorax auritus). Genetic variability was assessed using 60 individuals from three populations. All loci were variable with the number of alleles ranging from two to 17 per locus, and observed heterozygosity varying from 0.05 to 0.89. No loci showed signs of linkage disequilibrium and all loci conformed to Hardy–Weinberg equilibrium frequencies. Further, all loci amplified and were polymorphic in two related Phalacrocorax species. These loci should prove useful for population genetic studies of the double-crested cormorant and other pelecaniform species.

  11. Density of bunches of native bluebunch wheatgrass and alien crested wheatgrass

    SciTech Connect

    Rickard, W.H.

    1985-10-01

    The density of bunches of bluebunch wheatgrass in a natural undisturbed stand averaged 3.28 per m/sup 2/ as compared to 2.96 per m/sup 2/ for a nearby stand of crested wheatgrass that was planted 30 years ago. Bunch density was similar in both stands indicating that spacing is a response to an environment deficient in soil water. Bunches of crested wheatgrass on the average weighed 3.5 times more than bunches of bluebunch wheatgrass and they also produced a greater weight of seedheads.

  12. Avulsion fracture of the iliac crest in a child☆☆☆

    PubMed Central

    Mortati, Rafael Borghi; Borghi Mortati, Lucas; Silva Teixeira, Matheus; Itiro Takano, Marcelo; Armelin Borger, Richard

    2014-01-01

    Avulsion fractures of the apophysis of the iliac crest have rare incidence and are little known. In this article, we report the case of an 11-year-old female patient who presented this injury after indirect trauma. From careful radiographic analysis, an avulsion fracture of the iliac crest was identified. It was decided to use nonsurgical treatment comprising analgesia and load restriction. This case report emphasizes the importance of suspecting avulsion fractures in cases of low-energy trauma, and also guides the treatment, so as to prevent functional deficit and deformities. PMID:26229818

  13. Effects of epidermal growth factor on neural crest cells in tissue culture

    SciTech Connect

    Erickson, C.A.; Turley, E.A.

    1987-04-01

    Epidermal growth factor (EGF) stimulates the release of hyaluronic acid (HA) and chondroitin sulfate proteoglycan (CSPG) from quail trunk neural crest cultures in a dose-dependent fashion. It also promotes the expression of cell-associated heparan sulfate proteoglycan (HSPG) as detected by immunofluorescence and immunoprecipitation of the /sup 3/H-labeled proteoglycan. Furthermore, EGF stimulates (/sup 3/H)thymidine incorporation into total cell DNA. These results raise the possibility that EGF or an analogous growth factor is involved in regulation of neural crest cell morphogenesis.

  14. Wnt1 and BMP2: two factors recruiting multipotent neural crest progenitors isolated from adult bone marrow.

    PubMed

    Glejzer, A; Laudet, E; Leprince, P; Hennuy, B; Poulet, C; Shakhova, O; Sommer, L; Rogister, B; Wislet-Gendebien, S

    2011-06-01

    Recent studies have shown that neural crest-derived progenitor cells can be found in diverse mammalian tissues including tissues that were not previously shown to contain neural crest derivatives, such as bone marrow. The identification of those "new" neural crest-derived progenitor cells opens new strategies for developing autologous cell replacement therapies in regenerative medicine. However, their potential use is still a challenge as only few neural crest-derived progenitor cells were found in those new accessible locations. In this study, we developed a protocol, based on wnt1 and BMP2 effects, to enrich neural crest-derived cells from adult bone marrow. Those two factors are known to maintain and stimulate the proliferation of embryonic neural crest stem cells, however, their effects have never been characterized on neural crest cells isolated from adult tissues. Using multiple strategies from microarray to 2D-DIGE proteomic analyses, we characterized those recruited neural crest-derived cells, defining their identity and their differentiating abilities. PMID:20976520

  15. To proliferate or to die: role of Id3 in cell cycle progression and survival of neural crest progenitors

    PubMed Central

    Kee, Yun; Bronner-Fraser, Marianne

    2005-01-01

    The neural crest is a unique population of mitotically active, multipotent progenitors that arise at the vertebrate neural plate border. Here, we show that the helix-loop-helix transcriptional regulator Id3 has a novel role in cell cycle progression and survival of neural crest progenitors in Xenopus. Id3 is localized at the neural plate border during gastrulation and neurulation, overlapping the domain of neural crest induction. Morpholino oligonucleotide-mediated depletion of Id3 results in the absence of neural crest precursors and a resultant loss of neural crest derivatives. This appears to be mediated by cell cycle inhibition followed by cell death of the neural crest progenitor pool, rather than a cell fate switch. Conversely, overexpression of Id3 increases cell proliferation and results in expansion of the neural crest domain. Our data suggest that Id3 functions by a novel mechanism, independent of cell fate determination, to mediate the decision of neural crest precursors to proliferate or die. PMID:15769946

  16. The winged-helix transcription factor Foxd3 suppresses interneuron differentiation and promotes neural crest cell fate.

    PubMed

    Dottori, M; Gross, M K; Labosky, P; Goulding, M

    2001-11-01

    The neural crest is a migratory cell population that gives rise to multiple cell types in the vertebrate embryo. The intrinsic determinants that segregate neural crest cells from multipotential dorsal progenitors within the neural tube are poorly defined. In this study, we show that the winged helix transcription factor Foxd3 is expressed in both premigratory and migratory neural crest cells. Foxd3 is genetically downstream of Pax3 and is not expressed in regions of Pax3 mutant mice that lack neural crest, implying that Foxd3 may regulate aspects of the neural crest differentiation program. We show that misexpression of Foxd3 in the chick neural tube promotes a neural crest-like phenotype and suppresses interneuron differentiation. Cells that ectopically express Foxd3 upregulate HNK1 and Cad7, delaminate and emigrate from the neural tube at multiple dorsoventral levels. Foxd3 does not induce Slug and RhoB, nor is its ability to promote a neural crest-like phenotype enhanced by co-expression of Slug. Together these results suggest Foxd3 can function independently of Slug and RhoB to promote the development of neural crest cells from neural tube progenitors. PMID:11684651

  17. 76 FR 1149 - Eagle Crest Energy Company; Notice of Availability of the Draft Environmental Impact Statement...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-07

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Eagle Crest Energy Company; Notice of Availability of the Draft Environmental Impact Statement for the Eagle Mountain Pumped Storage Hydroelectric Project and Notice of Public Meetings December 23, 2010. In...

  18. FIELD PERFORMANCE OF WOODBURNING STOVES IN CRESTED BUTTE DURING THE 1991-92 HEATING SEASON

    EPA Science Inventory

    The report gives results of an evaluation of the 1991-92 field performance of 11 woodburning stoves in and around Crested Butte, CO. Measurements included particulate matter (PM), carbon monoxide, total unburned hydrocarbons, and weekly average burn rates. The monitored stoves in...

  19. Calibration of reaction rates for the CREST reactive-burn model

    NASA Astrophysics Data System (ADS)

    Handley, Caroline

    2015-06-01

    In recent years, the hydrocode-based CREST reactive-burn model has had success in modelling a range of shock initiation and detonation propagation phenomena in polymer bonded explosives. CREST uses empirical reaction rates that depend on a function of the entropy of the non-reacted explosive, allowing the effects of initial temperature, porosity and double-shock desensitisation to be simulated without any modifications to the model. Until now, the sixteen reaction-rate coefficients have been manually calibrated by trial and error, using hydrocode simulations of a subset of sustained-shock initiation gas-gun experiments and the detonation size-effect curve for the explosive. This paper will describe the initial development of an automatic method for calibrating CREST reaction-rate coefficients, using the well-established Particle Swarm Optimisation (PSO) technique. The automatic method submits multiple hydrocode simulations for each ``particle'' and analyses the results to determine the ``misfit'' to gas-gun and size-effect data. Over ~40 ``generations,'' the PSO code finds a best set of reaction-rate coefficients that minimises the misfit. The method will be demonstrated by developing a new CREST model for EDC32, a conventional high explosive.

  20. Disseminated pulmonary adiaspiromycosis in a crested porcupine (Hystrix cristata Linnaeus, 1758).

    PubMed

    Morandi, Federico; Galuppi, Roberta; Buitrago, Maria J; Delogu, Mauro; Lowenstine, Linda J; Panarese, Serena; Benazzi, Cinzia; Sarli, Giuseppe

    2012-04-01

    Adiaspiromycosis is primarily a necrotizing granulomatous pneumonia caused by a dimorphic fungus of the genus Emmonsia. A young crested porcupine (Hystrix cristata) found dead showed multiple fractures, chronic pleuritis, and granulomatous pneumonia. Microscopically, cystic structures were consistent with adiaspiromycosis by Emmonsia crescens. The diagnosis was confirmed using molecular methods. PMID:22493137

  1. Smad4 is required to regulate the fate of cranial neural crest cells

    PubMed Central

    Ko, Seung O; Chung, Il Hyuk; Xu, Xun; Oka, Shoji; Zhao, Hu; Cho, Eui Sic; Deng, Chuxia; Chai, Yang

    2009-01-01

    Smad4 is the central mediator for TGF-β/BMP signals, which are involved in regulating cranial neural crest (CNC) cell formation, migration, proliferation and fate determination. It is unclear whether TGF-β/BMP signals utilize Smad-dependent or –independent pathways to control the development of CNC cells. To investigate the functional significance of Smad4 in regulating CNC cells, we generated mice with neural crest specific inactivation of the Smad4 gene. Our study shows that Smad4 is not required for the migration of CNC cells, but is required in neural crest cells for the development of the cardiac outflow tract. Smad4 is essential in mediating BMP signaling in the CNC-derived ectomesenchyme during early stages of tooth development because conditional inactivation of Smad4 in neural crest derived cells results in incisor and molar development arrested at the dental lamina stage. Furthermore, Smad-mediated TGF-β/BMP signaling controls the homeobox gene patterning of oral/aboral and proximal/distal domains within the first branchial arch. At the cellular level, a Smad4-mediated downstream target gene(s) is required for the survival of CNC cells in the proximal domain of the first branchial arch. Smad4 mutant mice show underdevelopment of the first branchial arch and midline fusion defects. Taken together, our data show that TGF-β/BMP signals rely on Smad-dependent pathways in the ectomesenchyme to mediate epithelial-mesenchymal interactions that control craniofacial organogenesis. PMID:17964566

  2. Synthesis on accumulation of putative neurotransmitters by cultured neural crest cells

    SciTech Connect

    Maxwell, G.D.; Sietz, P.D.; Rafford, C.E.

    1982-07-01

    The events mediating the differentiation of embryonic neural crest cells into several types of neurons are incompletely understood. In order to probe one aspect of this differentiation, we have examined the capacity of cultured quail trunk neural crest cells to synthesize, from radioactive precursors, and store several putative neurotransmitter compounds. These neural crest cultures develop the capacity to synthesize and accumulate acetylcholine and the catecholamines norepinephrine and dopamine. In contrast, detectable but relatively little synthesis and accumulation of 5-hydroxytryptamine gamma-aminobutyric acid, or octopamine from the appropriate radiolabeled precursors were observed. The capacity for synthesis and accumulation of radiolabeled acetylcholine and catecholamines is very low or absent at 2 days in vitro. Between 3 and 7 days in vitro, there is a marked rise in both catecholamine and acetylcholine accumulation in the cultures. These findings suggest that, under the particular conditions used in these experiments, the development of neurotransmitter biosynthesis in trunk neural crest cells ijs restricted and resembles, at least partially, the pattern observed in vivo. The development of this capacity to synthesize and store radiolabeled acetylcholine and catecholamines from the appropriate radioactive precursors coincides closely with the development of the activities of the synthetic enzymes choline acetyltransferase and dopamine beta-hydroxylase reported by others.

  3. Id expression in amphioxus and lamprey highlights the role of gene cooption during neural crest evolution

    NASA Technical Reports Server (NTRS)

    Meulemans, Daniel; McCauley, David; Bronner-Fraser, Marianne

    2003-01-01

    Neural crest cells are unique to vertebrates and generate many of the adult structures that differentiate them from their closest invertebrate relatives, the cephalochordates. Id genes are robust markers of neural crest cells at all stages of development. We compared Id gene expression in amphioxus and lamprey to ask if cephalochordates deploy Id genes at the neural plate border and dorsal neural tube in a manner similar to vertebrates. Furthermore, we examined whether Id expression in these cells is a basal vertebrate trait or a derived feature of gnathostomes. We found that while expression of Id genes in the mesoderm and endoderm is conserved between amphioxus and vertebrates, expression in the lateral neural plate border and dorsal neural tube is a vertebrate novelty. Furthermore, expression of lamprey Id implies that recruitment of Id genes to these cells occurred very early in the vertebrate lineage. Based on expression in amphioxus we postulate that Id cooption conferred sensory cell progenitor-like properties upon the lateral neurectoderm, and pharyngeal mesoderm-like properties upon cranial neural crest. Amphioxus Id expression is also consistent with homology between the anterior neurectoderm of amphioxus and the presumptive placodal ectoderm of vertebrates. These observations support the idea that neural crest evolution was driven in large part by cooption of multipurpose transcriptional regulators from other tissues and cell types.

  4. An evaluation of the crest-stage gage program in Louisiana

    USGS Publications Warehouse

    Herbert, R.A.; Carlson, D.D.; Wiche, G.J.

    1985-01-01

    The crest-stage gage program in Louisiana was evaluated to determine if the data were adequate for use in developing regional flood-frequency equations and to determine if any crest-stage gages could be discontinued. An abundance of data at many crest-stage stations and a lack of data for urban area and flat-slope areas indicated a need for a shift in the number, type, and locations of gages. Extensive correlations and comparisons of annual peak flows and watershed characteristics of 96 sites resulted in a reduced network of 25 stations that could potentially be used as index sites. The adequacy of the reduced network for development and verification of regional flood-frequency equations was tested by comparing a set of regional flood-frequency equations developed using data from the full network with a set developed using data from the reduced network. The results indicate that the crest-stage gage network can be reduced to 25 stations and still provide adequate information for future flood-frequency analyses. (USGS)

  5. OXIDATIVE STRESS INDUCES CELL DEATH IN CD-1 MOUSE CRANIAL NEURAL CREST CELLS IN VITRO

    EPA Science Inventory

    OXIDATIVE STRESS INDUCES CELL DEATH IN CD-1 MOUSE CRANIAL NEURAL CREST CELLS IN VITRO. J.B. Smith, K.K. Sulik, E.S. Hunter III. University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.
    The induction of craniofacial defects by ethanol exposure is mediated in part by...

  6. DISCUSSION OF "BROAD-CRESTED WEIRS WITH RECTANGULAR COMPOUND CROSS SECTIONS"

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of interactive, easy-to-use design and calibration software in the past two decades has made broad-crested weirs with streamlined approaches one of the best available structure types for measuring open channel flows. Advantages include excellent accuracy, minimal head loss, adaptabi...

  7. 76 FR 15971 - Eagle Mountain Pumped Storage Hydroelectric Project; Eagle Crest Energy; Notice of Teleconference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Eagle Mountain Pumped Storage Hydroelectric Project; Eagle Crest Energy; Notice of Teleconference a. Date and Time of Meeting: Friday, April 15, 2011 at 9 a.m. (Pacific Time)....

  8. 78 FR 25263 - Eagle Mountain Pumped Storage Hydroelectric Project; Eagle Crest Energy; Notice of Meeting With...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Eagle Mountain Pumped Storage Hydroelectric Project; Eagle Crest Energy... Power Act), on the Eagle Mountain Pumped Storage Hydroelectric Project. e. All local, state, and...

  9. 76 FR 22699 - Eagle Mountain Pumped Storage Hydroelectric Project, Eagle Crest Energy; Notice of Teleconference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Eagle Mountain Pumped Storage Hydroelectric Project, Eagle Crest Energy; Notice of Teleconference a. Date and Time of Meeting: Friday, May 6, 2011 at 1 p.m. (Pacific Time)....

  10. Movement patterns of double-crested cormorants within aquaculture production areas in the Mississippi Delta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing numbers of Double-crested Cormorants (Phalacrocorax auritus) and other fish-eating birds at commercial aquaculture production facilities have resulted in biological, economical, and social conflicts. Unfortunately, there is not a concerted effort to determine over-wintering populations o...

  11. Decline of traditional rice farming constrains the recovery of the endangered Asian crested ibis (Nipponia nippon).

    PubMed

    Sun, Yiwen; Wang, Tiejun; Skidmore, Andrew K; Wang, Qi; Ding, Changqing

    2015-12-01

    Traditional agriculture benefits a rich diversity of plants and animals. The winter-flooded rice fields in the Qinling Mountains, China, are the last refuge for the endangered Asian crested ibis (Nipponia nippon), and intensive efforts have been made to protect this anthropogenic habitat. Analyses of multi-temporal satellite data indicate that winter-flooded rice fields have been continuously reduced across the current range of crested ibis during the past two decades. The rate of loss of these fields in the core-protected areas has unexpectedly increased to a higher level than that in non-protected areas in the past decade. The best fit (R (2) = 0.87) numerical response model of the crested ibis population shows that a reduction of winter-flooded rice fields decreases population growth and predicts that the population growth will be constrained by the decline of traditional winter-flooded rice fields in the coming decades. Our findings suggest that the decline of traditional rice farming is likely to continue to pose a threat to the long-term survival and recovery of the crested ibis population in China. PMID:25851484

  12. 50 CFR 21.48 - Depredation order for double-crested cormorants to protect public resources.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 9 2013-10-01 2013-10-01 false Depredation order for double-crested cormorants to protect public resources. 21.48 Section 21.48 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR (CONTINUED) TAKING, POSSESSION, TRANSPORTATION, SALE, PURCHASE, BARTER, EXPORTATION, AND IMPORTATION...

  13. Disparate osteogenic response of mandible and iliac crest bone marrow stromal cells to pamidronate

    PubMed Central

    Stefanik, D.; Sarin, J.; Lam, T.; Levin, L.; Leboy, PS; Akintoye, SO.

    2010-01-01

    OBJECTIVE Long-term administration of intravenous bisphosphonates like pamidronate is associated with jaw osteonecrosis but axial and appendicular bones are unaffected. Pathogenesis of bisphosphonate-associated jaw osteonecrosis may relate to skeletal-site specific effects of bisphosphonates on osteogenic differentiation of bone marrow stromal cells (BMSCs) of orofacial and axial/appendicular bones. This study evaluated and compared skeletal site-specific osteogenic response of mandible (orofacial bone) and iliac crest (axial bone) human BMSCs to pamidronate. MATERIALS AND METHODS Mandible and iliac crest BMSCs from six normal healthy volunteers were established in culture and tested with pamidronate to evaluate and compare cell survival, osteogenic marker alkaline phosphatase, osteoclast differentiation in co-cultures with CD34+ hematopoietic stem cells, gene expression of receptor activator of NFκB ligand (RANKL) and osteoprotegerin, and in vivo bone regeneration. BRESULTS Mandible BMSCs were more susceptible to pamidronate than iliac crest BMSCs based on decreased cell survival, lower alkaline phosphatase production and structurally less organized in vivo bone regeneration. Pamidronate promoted higher RANKL gene expression and osteoclast recruitment by mandible BMSCs. CONCLUSION Mandible and iliac crest BMSC survival and osteogenic differentiation are disparately affected by pamidronate to favor dysregulated mandible bone homeostasis. PMID:18938273

  14. Early development of the neural plate, neural crest and facial region of marsupials

    PubMed Central

    SMITH, KATHLEEN K.

    2001-01-01

    Marsupial mammals have a distinctive reproductive strategy. The young are born after an exceptionally short period of organogenesis and are consequently extremely altricial. Yet because they must be functionally independent in an essentially embryonic condition, the marsupial neonate exhibits a unique suite of adaptations. In particular, certain bones of the facial region, most cranial musculature and a few additional structures are accelerated in their development. In contrast, central nervous system structures, especially the forebrain, are markedly premature at birth, resembling an embryonic d 11 or 12 mouse. This review examines the developmental processes that are modified to produce these evolutionary changes. The focus is on the early development of the neural plate, neural crest and facial region in the marsupial, Monodelphis domestica, compared with patterns reported for rodents. Neural crest begins differentiation and migration at the neural plate stage, which results in large accumulations of neural crest in the facial region at an early stage of development. The early accumulation of neural crest provides the material for the accelerated development of oral and facial structures. The first arch region is massive in the early embryo, and the development of the olfactory placode and frontonasal region is advanced relative to the forebrain region. The development of the forebrain is delayed in marsupials relative to the hindbrain or facial region. These observations illustrate how development may be modified to produce evolutionary changes that distinguish taxa. Further, they suggest that development is not necessarily highly conserved, but instead may be quite plastic. PMID:11523813

  15. The hypoxia factor Hif-1α controls neural crest chemotaxis and epithelial to mesenchymal transition

    PubMed Central

    Barriga, Elias H.; Maxwell, Patrick H.

    2013-01-01

    One of the most important mechanisms that promotes metastasis is the stabilization of Hif-1 (hypoxia-inducible transcription factor 1). We decided to test whether Hif-1α also was required for early embryonic development. We focused our attention on the development of the neural crest, a highly migratory embryonic cell population whose behavior has been likened to cancer metastasis. Inhibition of Hif-1α by antisense morpholinos in Xenopus laevis or zebrafish embryos led to complete inhibition of neural crest migration. We show that Hif-1α controls the expression of Twist, which in turn represses E-cadherin during epithelial to mesenchymal transition (EMT) of neural crest cells. Thus, Hif-1α allows cells to initiate migration by promoting the release of cell–cell adhesions. Additionally, Hif-1α controls chemotaxis toward the chemokine SDF-1 by regulating expression of its receptor Cxcr4. Our results point to Hif-1α as a novel and key regulator that integrates EMT and chemotaxis during migration of neural crest cells. PMID:23712262

  16. Deubiquitinase–based analysis of ubiquitin chain architecture using Ubiquitin Chain Restriction (UbiCRest)

    PubMed Central

    Komander, David

    2016-01-01

    Protein ubiquitination is a versatile protein modification that regulates virtually all cellular processes. This versatility originates from polyubiquitin chains, which can be linked in eight distinct ways. The combinatorial complexity of eight linkage types in homotypic (one chain type per polymer) and heterotypic (multiple linkage types per polymer) chains poses significant problems for biochemical analysis. Here we describe UbiCRest, in which substrates (ubiquitinated proteins or polyubiquitin chains) are treated with a panel of linkage-specific deubiquitinating enzymes (DUBs) in parallel reactions, followed by gel-based analysis. UbiCRest can be used to show that a protein is ubiquitinated, to identify which linkage type(s) are present on polyubiquitinated proteins and to assess the architecture of heterotypic polyubiquitin chains. DUBs used in UbiCRest can be obtained commercially; however, we include details for generating a toolkit of purified DUBs and for profiling their linkage preferences in vitro. UbiCRest is a qualitative method that yields insights into ubiquitin chain linkage types and architecture within hours, and it can be performed on western blotting quantities of endogenously ubiquitinated proteins. PMID:25633630

  17. 50 CFR 21.47 - Depredation order for double-crested cormorants at aquaculture facilities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 9 2012-10-01 2012-10-01 false Depredation order for double-crested cormorants at aquaculture facilities. 21.47 Section 21.47 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR (CONTINUED) TAKING, POSSESSION, TRANSPORTATION, SALE, PURCHASE, BARTER, EXPORTATION, AND IMPORTATION...

  18. Solar Simulation for the CREST Preflight Thermal-Vacuum Test at B-2

    NASA Technical Reports Server (NTRS)

    Ziemke, Robert A.

    2012-01-01

    In June 2011, the multi-university sponsored Cosmic Ray Electron Synchrotron Telescope (CREST) has undergone thermal-vacuum qualification testing at the NASA Glenn Research Center (GRC), Plum Brook Station, Sandusky, Ohio. The testing was performed in the B-2 Space Propulsion Facility vacuum chamber. The CREST was later flown over the Antarctic region as the payload of a stratospheric balloon. Solar simulation was provided by a system of planar infrared lamp arrays specifically designed for CREST. The lamp arrays, in conjunction with a liquid-nitrogen-cooled cold wall, achieved the required thermal conditions for the qualification tests. The following slides accompanied the presentation of the report entitled Solar Simulation for the CREST Preflight Thermal-Vacuum Test at B-2, at the 27th Aerospace Testing Seminar, October 2012. The presentation described the test article, the test facility capability, the solar simulation requirements, the highlights of the engineering approach, and the results achieved. The presentation was intended to generate interest in the report and in the B-2 test facility.

  19. Abundances of coplanted native bunchgrasses and crested wheatgrass after 13 years

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crested wheatgrass (Agropyron cristatum [L] Gaertm) has been seeded on over 5 million hectares in western North America because it more readily establishes than native bunchgrasses. Currently, there is substantial interest in re-establishing native species in sagebrush steppe, but efforts to reintro...

  20. Crested Wheatgrass Defoliation Intensity and Season of Use on Medusahead Invasion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to determine the effects of crested wheatgrass defoliation intensity and timing on medusahead density and biomass. Eighteen treatments (six defoliation levels, three seasons of defoliation) were applied to 21.5-ft2 plots on two sites with varying clay content. Plant...

  1. Nest box use and productivity of great crested flycatchers in prescribed-burned longleaf pine forests

    USGS Publications Warehouse

    White, D.H.; Seginak, J.T.

    2000-01-01

    Managing for the endangered Red-cockaded Woodpecker (Picoides borealis) on federal lands requires burning large tracts of mature pine forests every 3-5 yr. Many cavity trees that serve as potential nest sites for primary and secondary hole-nesting birds are destroyed by fire. We assessed the efficacy of a nest box program for the Great Crested Flycatcher (Myiarchus crinitus) at Carolina Sandhills National Wildlife Refuge, an area intensively managed for Red-cockaded Woodpeckers. During 1996-1998, we installed and monitored 330 (30 in each of 11 sites) nest boxes in mature (>60 yr) longleaf pine (Pinus palustris) tracts that were burned either in April-June (warm season) or December-March (cool season). Prescribed-burned sites were nearly devoid of snags; we estimated only 0.8/ ha in cool-season burns and 1.7/ha in warm-season burns. Great Crested Flycatchers built nests in 20% of the boxes available to them. Clutch sizes were larger in warm-season burns than in cool-season burns, but fledging success (fledglings/nest hatching -1 egg) was lower. Twenty-two of 59 Great Crested Flycatcher nests were depredated and the proportions in each burn class were similar. We recommend the installation of nest boxes for Great Crested Flycatchers in prescribed-burned pine forests, but additional research is needed in these habitats on nest depredation rates and causes.

  2. Donor Site Evaluation: Anterior Iliac Crest Following Secondary Alveolar Bone Grafting

    PubMed Central

    Vura, Nandagopal; Reddy K., Rajiv; R., Sudhir; G., Rajasekhar; Kaluvala, Varun Raja

    2013-01-01

    Introduction: The use of autogenous bone graft for Secondary alveolar bone grafting is well established in the treatment of cleft lip and palate patients. Aims and Objectives: To evaluate post-operative morbidity of anterior iliac crest graft after secondary alveolar bone grafting in cleft patients. Material and Methods: Forty patients during the period from July 2008 to March 2013, who underwent secondary alveolar bone grafting by harvesting graft from anterior iliac crest in Mamata Dental Hospital, Khammam, Andhra Pradesh, India are included in the present study. Unilateral and bilateral cleft patients who had undergone secondary alveolar bone grafting (SABG) with anterior iliac crest as their donor site have been selected and post- operative complications from the surgery were evaluated with the help of a questionnaire which included pain, gait disturbances, numbness and scar problems (infection, irritation). Results: Patients who were operated gave maximum score for pain as 8 on visual analogue scale. No pain was observed in any of the cases after 8 days, gait disturbances were seen in all patients (limping) for 2-6 days, there was no post-operative numbness with all the patients returning to their routine in 6- 15 days and 90% of the patients gave a satisfied response towards scar. Conclusion: From the results in our study the morbidity after harvesting bone from iliac crest was found to be moderate to low, which had minimal complications and were well tolerated and greater acceptance from the patient. PMID:24392424

  3. HALOACETIC ACIDS AND KINASE INHIBITORS PERTURB MOUSE NEURAL CREST CELLS IN VITRO

    EPA Science Inventory

    HUNTER, E.S.1, J. SMITH2, J. ANDREWS1. 1 Reproductive Toxicology Division, NHEERL, US EPA, Research Triangle Park and 2 Department of Cell and Developmental Biology, UNC-CH, Chapel Hill, North Carolina. Haloacetic acids and kinase inhibitors perturb mouse neural crest cells in vi...

  4. Actin capping protein CAPZB regulates cell morphology, differentiation, and neural crest migration in craniofacial morphogenesis†.

    PubMed

    Mukherjee, Kusumika; Ishii, Kana; Pillalamarri, Vamsee; Kammin, Tammy; Atkin, Joan F; Hickey, Scott E; Xi, Qiongchao J; Zepeda, Cinthya J; Gusella, James F; Talkowski, Michael E; Morton, Cynthia C; Maas, Richard L; Liao, Eric C

    2016-04-01

    CAPZB is an actin-capping protein that caps the growing end of F-actin and modulates the cytoskeleton and tethers actin filaments to the Z-line of the sarcomere in muscles. Whole-genome sequencing was performed on a subject with micrognathia, cleft palate and hypotonia that harbored a de novo, balanced chromosomal translocation that disrupts the CAPZB gene. The function of capzb was analyzed in the zebrafish model. capzb(-/-) mutants exhibit both craniofacial and muscle defects that recapitulate the phenotypes observed in the human subject. Loss of capzb affects cell morphology, differentiation and neural crest migration. Differentiation of both myogenic stem cells and neural crest cells requires capzb. During palate morphogenesis, defective cranial neural crest cell migration in capzb(-/-) mutants results in loss of the median cell population, creating a cleft phenotype. capzb is also required for trunk neural crest migration, as evident from melanophores disorganization in capzb(-/-) mutants. In addition, capzb over-expression results in embryonic lethality. Therefore, proper capzb dosage is important during embryogenesis, and regulates both cell behavior and tissue morphogenesis. PMID:26758871

  5. Combinatorial transcriptional interaction within the Cardiac Neural Crest: a pair of HANDs in heart formation

    PubMed Central

    Firulli, Anthony B.; Conway, Simon J.

    2008-01-01

    The cardiac neural crest migrate from rostral dorsal neural folds and populate the branchial arches, which directly contribute to cardiac-outflow structures. Although neural crest cell specification is associated with a number of morphogenic factors, little is understood about the mechanisms by which transcription factors actually implement the transcriptional programs that dictate cell migration and later the differentiation into the proper cell types within the heart. It is clear from genetic evidence that members of the paired box family and basic helix-loop-helix (bHLH) transcription factors from the twist family of proteins are expressed in and play an important function in cardiac neural crest specification and differentiation. Interestingly, both paired box and bHLH factors can function as dimers and in the case of twist family bHLH factors partner choice can clearly dictate a change in transcriptional program. The focus of this review is to consider the role that the protein-protein interactions of these transcription factors may play determining cardiac neural crest specification and differentiation and how genetic alteration of transcription factor stoichiometry within the cell may reflect more than a simple null event. PMID:15269889

  6. CSUB CREST Research on Climate Change and the San Joaquin Valley, CA

    NASA Astrophysics Data System (ADS)

    Krugh, W. C.; Negrini, R. M.; Baron, D.; Gillespie, J.; Horton, R. A.; Montoya, E.; Cruz-Boone, C.; Andrews, G. D.; Guo, J.

    2015-12-01

    As part of the NSF-supported Centers for Excellence in Science and Technology (CREST), student and faculty researchers at California State University, Bakersfield (CSUB) have been investigating the regional impacts of climate change as well as evaluating the potential of local contributions to its abatement. Highlights of this research include; 1) the development of a high-resolution climate record from Tulare Lake sediments that spans the past 20,000 years, 2) the quantitative analysis and prediction of climate change impacts on Sierra Nevada snowpack, 3) the detailed subsurface characterization of San Joaquin Valley oilfields targeted for CO2 sequestration, and 4) the evaluation of proposed host rock suitability under simulated CO2 injection conditions. To date, CSUB CREST supported research has resulted in 26 contributions to peer-reviewed journals (currently published or in-review). A primary goal of CSUB CREST is to improve the recruitment, retention, and success of students from the local community, the majority of whom are from backgrounds under-represented in STEM disciplines. More than 28 students have been directly involved in the basic and applied research projects supported by this program. The majority of these students have received, or are on track to receive, an M.S. degree and have ultimately gained employment in a STEM field or been accepted into a Ph.D. program. This presentation, and others in this session, will focus on the accomplishments, challenges, and strategies for success gleaned from CSUB CREST Phase 1.

  7. Culture conditions affect the cholinergic development of an isolated subpopulation of chick mesencephalic neural crest cells.

    PubMed

    Barald, K F

    1989-10-01

    Although neural crest cells are known to be very responsive to environmental cues during their development, recent evidence indicates that at least some subpopulations may be committed to a specific differentiation program prior to migration. Because the neural crest is composed of a heterogeneous mixture of cells that contributes to many vertebrate cell lineages, assessing the properties of specific subpopulations and the effect of the environment on their development has been difficult. To address this problem, we have isolated a pure subpopulation of chick mesencephalic neural crest cells by fluorescence no-flow cytometry after labeling them with monoclonal antibodies (Mabs) to a 75-kDa cell surface antigen that is associated with high affinity choline uptake. When cultures of chick mesencephalic neural crest cells are labeled with these Mabs and a fluorescent second step antibody, approximately 5% of the cells are antigen-positive (A+). After sorting, 100% of the resulting cultured mesencephalic neural crest cells are A+. The Mabs we used also label all of the neurons of the embryonic chick and quail ciliary ganglion in vivo and in vitro. We have compared the effect of various cell culture media on the isolated neural crest subpopulation and the heterogeneous chick mesencephalic neural crest from which it was derived. A+ cells were passaged and grown in a variety of media, each of which differently affected its characteristics and development. A+ cells proliferated in the presence of 15% fetal bovine serum (FBS) and high concentrations (10-15%) of chick embryo extract, but did not differentiate, although they retained basal levels of choline acetyltransferase (ChAT) activity. However, in chick serum and high (25 mM as opposed to 7 mM) K+, and heart-, iris-, or lung-conditioned medium, all of which are known to promote survival and/or cholinergic development of ciliary ganglion neurons, the cells ceased to proliferate and all of the cells in the culture became

  8. Ontogeny in the tube-crested dinosaur Parasaurolophus (Hadrosauridae) and heterochrony in hadrosaurids

    PubMed Central

    Chok, Derek J.; Herrero, Annisa; Scolieri, Brandon; Werning, Sarah

    2013-01-01

    The tube-crested hadrosaurid dinosaur Parasaurolophus is remarkable for its unusual cranial ornamentation, but little is known about its growth and development, particularly relative to well-documented ontogenetic series for lambeosaurin hadrosaurids (such as Corythosaurus, Lambeosaurus, and Hypacrosaurus). The skull and skeleton of a juvenile Parasaurolophus from the late Campanian-aged (∼75.5 Ma) Kaiparowits Formation of southern Utah, USA, represents the smallest and most complete specimen yet described for this taxon. The individual was approximately 2.5 m in body length (∼25% maximum adult body length) at death, with a skull measuring 246 mm long and a femur 329 mm long. A histological section of the tibia shows well-vascularized, woven and parallel-fibered primary cortical bone typical of juvenile ornithopods. The histological section revealed no lines of arrested growth or annuli, suggesting the animal may have still been in its first year at the time of death. Impressions of the upper rhamphotheca are preserved in association with the skull, showing that the soft tissue component for the beak extended for some distance beyond the limits of the oral margin of the premaxilla. In marked contrast with the lengthy tube-like crest in adult Parasaurolophus, the crest of the juvenile specimen is low and hemicircular in profile, with an open premaxilla-nasal fontanelle. Unlike juvenile lambeosaurins, the nasal passages occupy nearly the entirety of the crest in juvenile Parasaurolophus. Furthermore, Parasaurolophus initiated development of the crest at less than 25% maximum skull size, contrasting with 50% of maximum skull size in hadrosaurs such as Corythosaurus. This early development may correspond with the larger and more derived form of the crest in Parasaurolophus, as well as the close relationship between the crest and the respiratory system. In general, ornithischian dinosaurs formed bony cranial ornamentation at a relatively younger age and smaller size

  9. Differential response in chick survival to diet in least and crested auklets

    USGS Publications Warehouse

    Gall, A.E.; Roby, D.D.; Irons, D.B.; Rose, I.C.

    2006-01-01

    Least auklets Aethia pusilla and crested auklets A. cristatella are abundant planktivorous seabirds found throughout the Bering Sea and are inextricably linked to the secondary productivity of this northern marine ecosystem. We assessed the relationship between productivity and diet in least and crested auklets by examining breeding chronology, daily survival rates (DSR) of chicks, and nestling diet composition at 2 mixed colonies on St. Lawrence Island in the northern Bering Sea during the 2000 to 2002 breeding seasons. Nestlings of both least and crested auklets hatched earlier, had higher survival rates, and were fed more of the large, oceanic copepod Neocalanus cristatus in 2002 compared to the 2 yr of lower chick survival. In contrast, during the year of lowest DSR for both auklet species (2001), the small copepod Calanus marshallae was more prevalent in the diet of least auklets and the mid-sized copepod N. flemingeri was more prevalent in the diet of crested auklets compared to the other 2 yr. The prevalence of oceanic copepods in meals fed to chicks explained much of the annual variation in DSR in least auklets. Interannual differences in timing of nest initiation, nest survival, and diet of least and crested auklets may be associated with the strength of the cold, nutrient-rich Anadyr Current, which passes in close proximity to St. Lawrence Island and has important influences on zooplankton productivity and distribution. Auklet productivity and diet composition may serve as key indicators in the overall effort to monitor the impact of climate change on the productivity of the Bering Sea. ?? Inter-Research 2006.

  10. Xenopus ADAM19 is involved in neural, neural crest and muscle development

    PubMed Central

    Neuner, Russell; Cousin, Hélène; McCusker, Catherine; Coyne, Michael; Alfandari, Dominique

    2009-01-01

    ADAM19 is a member of the meltrin subfamily of ADAM metalloproteases. In Xenopus, ADAM19 is present as a maternal transcript. Zygotic expression starts during gastrulation and is apparent in the dorsal blastopore lip. ADAM19 expression through neurulation and tailbud formation becomes enriched in dorsal structures such as the neural tube, the notochord and the somites. Using morpholino knock-down, we show that a reduction of ADAM19 protein in gastrula stage embryos results in a decrease of Brachyury expression in the notochord concomitant with an increase in the dorsal markers, Goosecoid and Chordin. These changes in gene expression are accompanied by a decrease in phosphorylated AKT, a downstream target of the EGF signaling pathway, and occur while the blastopore closes at the same rate as the control embryos. During neurulation and tailbud formation, ADAM19 knock-down induces a reduction of the neural markers N-tubulin and NRP1 but not Sox2. In the somitic mesoderm, the expression of MLC is also decreased while MyoD is not. ADAM19 knockdown also reduces neural crest markers prior to cell migration. Neural crest induction is also decreased in embryos treated with an EGF receptor inhibitor suggesting that this pathway is necessary for neural crest cell induction. Using targeted knockdown of ADAM19 we show that the reduction of neural and neural crest markers is cell autonomous and that the migration if the cranial neural crest is perturbed. We further show that ADAM19 protein reduction affects somite organization, reduces 12–101 expression and perturbs fibronectin localization at the intersomitic boundary. PMID:19027850

  11. A pilot study investigating the utilization of crest pads for treatment of toe callus and ulceration.

    PubMed

    Melo, Monica; Bernecker, Tricia; McCullough, James; Hong, John; Trumbauer, Jane Scott; Miller, Mary Ellen

    2015-12-01

    Patients with lesser-toe deformities are at increased risk of developing calluses and ulcers on the distal ends of the affected digits because of the increased pressures applied to these areas. The number of diabetic patients in the United States continues to increase, along with associated comorbidities such as peripheral vascular disease and peripheral neuropathy. These conditions predispose patients to developing foot ulcerations, especially if foot deformities are present. Crest pads are a simple-to-make, inexpensive option to treat calluses and ulcerations on the distal ends of digits; however, there is no research available that support their use. Crest pads consist of rolled gauze covered in moleskin, with a large opening that fits over several toes and lies on the dorsal aspect of the foot, with the padded portion resting under the toes. Over several days of use, the pad molds to the plantar aspect of the toes, offloading pressure from the distal end of the affected digit(s). The sample was obtained through a retrospective chart review of patients identified as having had at least one nail care visit and at least one follow-up visit at a vascular surgery practice between August 2011 and December 2014. Potential subjects with toe deformities who presented with callus or ulcer on the distal end of a digit were considered for inclusion, if they received a crest pad as part of their treatment plan. The scholarly project was a preintervention or postintervention design with subjects acting as their own controls. McNemar's test was used to analyze the results which were statistically significant (P < .0001 at first callus follow-up and P = .0002 at second callus follow-up) for callus, hemorrhagic callus, and/or ulcer improvement following the crest pad intervention. The results of this scholarly project support the use of crest pads in patients with lesser-toe deformities to treat distal toe calluses and/or ulcerations. PMID:26567055

  12. A New Brachylophosaurin Hadrosaur (Dinosauria: Ornithischia) with an Intermediate Nasal Crest from the Campanian Judith River Formation of Northcentral Montana

    PubMed Central

    Freedman Fowler, Elizabeth A.; Horner, John R.

    2015-01-01

    Background Brachylophosaurini is a clade of hadrosaurine dinosaurs currently known from the Campanian (Late Cretaceous) of North America. Its members include: Acristavus gagslarsoni, which lacks a nasal crest; Brachylophosaurus canadensis, which possesses a flat paddle-shaped nasal crest projecting posteriorly over the dorsal skull roof; and Maiasaura peeblesorum, which possesses a dorsally-projecting nasofrontal crest. Acristavus, from the lower Two Medicine Formation of Montana (~81–80 Ma), is hypothesized to be the ancestral member of the clade. Brachylophosaurus specimens are from the middle Oldman Formation of Alberta and equivalent beds in the Judith River Formation of Montana; the upper Oldman Formation is dated 77.8 Ma. Methodology/Principal Findings A new brachylophosaurin hadrosaur, Probrachylophosaurus bergei (gen. et sp. nov.) is described and phylogenetically analyzed based on the skull and postcranium of a large individual from the Judith River Formation of northcentral Montana (79.8–79.5 Ma); the horizon is equivalent to the lower Oldman Formation of Alberta. Cranial morphology of Probrachylophosaurus, most notably the nasal crest, is intermediate between Acristavus and Brachylophosaurus. In Brachylophosaurus, the nasal crest lengthens and flattens ontogenetically, covering the supratemporal fenestrae in large adults. The smaller nasal crest of Probrachylophosaurus is strongly triangular in cross section and only minimally overhangs the supratemporal fenestrae, similar to an ontogenetically earlier stage of Brachylophosaurus. Sutural fusion and tibial osteohistology reveal that the holotype of Probrachylophosaurus was relatively more mature than a similarly large Brachylophosaurus specimen; thus, Probrachylophosaurus is not simply an immature Brachylophosaurus. Conclusions/Significance The small triangular posteriorly oriented nasal crest of Probrachylophosaurus is proposed to represent a transitional nasal morphology between that of a non-crested

  13. The role of Foxi family transcription factors in otic placode and neural crest cell development

    PubMed Central

    Edlund, Renée K.; Birol, Onur; Groves, Andrew K.

    2015-01-01

    The mammalian outer, middle and inner ears have different embryonic origins and evolved at different times in the vertebrate lineage. The outer ear is derived from first and second branchial arch ectoderm and mesoderm, the middle ear ossicles are derived from neural crest mesenchymal cells that invade the first and second branchial arches, whereas the inner ear and its associated vestibule-acoustic (VIIIth) ganglion are derived from the otic placode. In this review, we discuss recent findings in the development of these structures and describe the contributions of members of a Forkhead transcription factor family, the Foxi family to their formation. Foxi transcription factors are critical for formation of the otic placode, survival of the branchial arch neural crest, and developmental remodeling of the branchial arch ectoderm. PMID:25662269

  14. Chemical immobilization of crested porcupines with tiletamine HCl and zolazepam HCl (Zoletil) under field conditions.

    PubMed

    Massolo, Alessandro; Sforzi, Andrea; Lovari, Sandro

    2003-07-01

    The combination of tiletamine HCl and zolazepam HCl has been used on many species of wild mammals. Short induction time, low dosage, satisfactory safety margins, relatively constant immobilization time, and smooth recovery are benefits reported. This combination (Zoletil 100) was used during a study on behavioural ecology of the crested porcupine (Hystrix cristata) in a Mediterranean coastal area (Maremma Regional Park, Tuscany, Italy). We used this mixture 42 times on 31 individuals. Mean adult dose was (+/- SE) 7.24 +/- 0.37 mg/kg (74.0 +/- 3.0 mg/individual). Average adult induction time was 5.3 min (+/- 1.1) and average adult immobilization time was 22.6 min (+/- 6.0). One adult male porcupine died after chemical restraints. The use of tiletamine-zolazepam seems adequate for chemical immobilization of crested porcupines under field conditions, mainly because of its short induction time, small volume to be injected and wide safety margin. PMID:14567239

  15. Mandibular reconstruction using free vascularized iliac crest grafts and dental implants

    PubMed Central

    MOLDOVAN, IULIU; JUNCAR, MIHAI; DINU, CRISTIAN; ONISOR-GLIGOR, FLORIN; ROTAR, HORATIU; BRAN, SIMION; BACIUT, GRIGORE

    2015-01-01

    Background and aim The mandible is frequently affected by tumor masses present in the oral cavity and is included in the tumor ablation procedure, with major functional and esthetic consequences for the patient. A method of high current interest in mandibular reconstruction is based on the use of free vascularized iliac crest grafts, followed by reconstruction using dental implants. Methods This study presents the case of four patients benefiting from this treatment method, and monitors the treatment stages and their clinical evolution after mandibular reconstruction and dental implant placement. Results The postoperative evolution of the patients was favorable, with the integration of the iliac crest grafts and dental implants. After prosthetic loading, the masticatory as well as the esthetic function of the patients was restored to a standard close to the initial one. Conclusions This mandibular reconstruction method proved to be effective, with a high degree of reliability and a significant improvement of the patients’ quality of life. PMID:26609275

  16. Implant-Prosthetic Rehabilitation in Bilateral Agenesis of Maxillary Lateral Incisors with a Mini Split Crest

    PubMed Central

    Figliuzzi, M. M.; Giudice, A.; Pileggi, S.; Pacifico, D.; Marrelli, M.; Tatullo, M.; Fortunato, L.

    2016-01-01

    The reported clinical case describes the surgical procedure of ridge augmentation by using a “split crest” technique with a partial thickness flap and a subsequent implant-prosthetic rehabilitation aimed at treating a bilateral agenesis of the upper lateral incisors. In such cases with vestibule-palatal and mesial-distal scarce bone thicknesses associated with the need of a proper functional and aesthetic rehabilitation, the split crest technique is particularly suitable. In the case we reported, because of the poor bone thicknesses, we performed a minimally invasive split crest which allowed a correct insertion of the fixtures. This technique allowed us to achieve an optimal functional and aesthetic rehabilitation; moreover, we obtained a good emergency profile, ensuring the vitality of the close teeth and ensuring a good primary stability and the following osseointegration of dental implants. PMID:27190658

  17. Vasculitis in systemic sclerosis: association with Sjögren's syndrome and the CREST syndrome variant.

    PubMed

    Oddis, C V; Eisenbeis, C H; Reidbord, H E; Steen, V D; Medsger, T A

    1987-10-01

    We describe 7 patients with established systemic sclerosis who developed clinical evidence of vasculitis 1 to 33 (mean 12.7) years after the first symptoms of scleroderma. Six had the CREST variant of systemic sclerosis and also had features of Sjögren's syndrome (SS). Five of 6 patients tested had serum anti-SSA (Ro) antibodies. Vasculitis presented primarily as cutaneous lesions with ulceration and/or mononeuritis multiplex, and 6 patients had severe systemic manifestations. Vasculitis was histopathologically documented in 6 cases in biopsies of skin (4 of 4), muscle (2 of 3) and sural nerve (3 of 3). Patients with systemic sclerosis with CREST syndrome and SS appear to be at increased risk to develop vasculitis. PMID:3430523

  18. What Crested Butte Mountain Resort Feels the Ski Industry Is, In General, Looking for in College Graduates.

    ERIC Educational Resources Information Center

    Jernigan, Rick

    This paper describes general employment requirements for employment candidates in the skiing industry, as seen by Crested Butte Mountain Resort personnel. General educational requirements are primarily business skills, including: communications, computers, math, finance, accounting, economics, personnel administration, and psychology. Other…

  19. Iliac Crest Donor Site for Children With Cleft Lip and Palate Undergoing Alveolar Bone Grafting: A Long-term Assessment.

    PubMed

    Wheeler, Jonathan; Sanders, Megan; Loo, Stanley; Moaveni, Zac; Bartlett, Glenn; Keall, Heather; Pinkerton, Mark

    2016-05-01

    The authors aimed to accurately assess the donor site morbidity from iliac crest bone grafts for secondary bone grafting in patients with cleft lip and palate alveolar defects. Fifty patients between 3 months and 10 years following alveolar bone grafting for cleft lip and palate were entered into the study. Two-thirds of patients had no significant concerns about the donor site. The remaining third had some concerns about the appearance of their hips and less than 10% of patients expressing strong agreement with statements about concerns with shape, appearance, and self-consciousness about the iliac crest donor site. Examination findings showed the average length of scar being 5.4 cm and a third of patients having some minor palpable boney irregularities of the iliac crest. The authors found that the alveolar crest donor site is well tolerated by patients long term but has a measurable morbidity long term. PMID:27035602

  20. Habitat use and food selection of small mammals near a sagebrush/crested wheatgrass interface in southeastern Idaho

    SciTech Connect

    Koehler, D.K. ); Anderson, S.H. )

    1991-09-01

    Research has been conducted on various aspects of the ecology of wildlife residing on and adjacent to the Subsurface Disposal Area (SDA) and one other low-level radioactive waste disposal site on the Idaho National Engineering Laboratory (INEL) in southeastern Idaho. Habitat use and food selection data were collected for deer mice (Peromyscus maniculatus), montane voles (Microtus montanus), Ord's kangaroo rats (Dipodomys ordii), and Townsend's ground squirrels (Spermophilus townsendii) near a sagebrush (Artemisia tridentata)/crested wheatgrass (Agropyron cristatum) interface. Significantly more captures occurred in the native sagebrush habitat than in areas planted in crested wheatgrass or in disturbed sites. Crested wheatgrass, a prolific seed producer, still accounted for over 30% of the total captures. Montane voles and Townsend's ground squirrels (during periods of aboveground activity) used the crested wheatgrass habitat throughout the summer, while deer mice and Ord's kangaroo rats exhibited heavy use after seed set.

  1. Biomechanical loading test on reconstructed mandibles with fibular, iliac crest or scapula graft: a comparative study.

    PubMed

    Grohmann, Isabella; Raith, Stefan; Mücke, Thomas; Stimmer, Herbert; Rohleder, Nils; Kesting, Marco R; Hölzle, Frank; Steiner, Timm

    2015-10-01

    Advantages and disadavantages of the three most commonly-used bone grafts for mandibular reconstruction are widely known, but biomechanical experimental studies are rare. We have done loading tests on cadaveric mandibles reconstructed with fibular, iliac crest, and scapular grafts using 3 different osteosynthesis systems to detect and compare their primary stability. Loading tests were done on mandibles with grafts from the fibula and iliac crest and published previously. A 4.5cm paramedian L-type defect was reconstructed with scapula using 2 monocortical non-locking plates, 2 monocortical locking plates, or a single bicortical locking plate/fracture gap in 18 human cadaveric mandibles. These were loaded on to the "Mandibulator" test bench and the movement of fragments in 3 dimensions was assessed and quantified by a PONTOS® optical measurement system. Comparison of the osteosynthesis groups showed that the miniplate was significantly superior to the 6-hole TriLock® plate for both fibular and iliac crest grafts. The fibular graft gave greater stability than the iliac crest and scapular grafts for all 3 osteosynthesis systems. All bony specimens offered sufficient resistance to mechanical stress within the recognised range of biting forces after mandibular reconstruction, independently of the choice of bone graft and osteosynthesis system used. Anatomical and surgical advantages need to be taken into account when choosing a graft. Stability can be maximised with a fibular graft, and further optimised by enlarging the binding area by using the "double barrel" method. Computer simulated experiments could segregate factors that biased results, such as morphological differences among cadavers. PMID:26088156

  2. The invasive annual cheatgrass releases more nitrogen than crested wheatgrass through root exudation and senescence.

    PubMed

    Morris, Kendalynn A; Stark, John M; Bugbee, Bruce; Norton, Jeanette M

    2016-08-01

    Plant-soil feedbacks are an important aspect of invasive species success. One type of feedback is alteration of soil nutrient cycling. Cheatgrass invasion in the western USA is associated with increases in plant-available nitrogen (N), but the mechanism for this has not been elucidated. We labeled cheatgrass and crested wheatgrass, a common perennial grass in western rangelands, with (15)N-urea to determine if differences in root exudates and turnover could be a mechanism for increases in soil N. Mesocosms containing plants were either kept moist, or dried out during the final 10 days to determine the role of senescence in root N release. Soil N transformation rates were determined using (15)N pool dilution. After 75 days of growth, cheatgrass accumulated 30 % more total soil N and organic carbon than crested wheatgrass. Cheatgrass roots released twice as much N as crested wheatgrass roots (0.11 vs. 0.05 mg N kg(-1) soil day(-1)) in both soil moisture treatments. This occurred despite lower root abundance (7.0 vs. 17.3 g dry root kg(-1) soil) and N concentration (6.0 vs. 7.6 g N kg(-1) root) in cheatgrass vs. crested wheatgrass. We propose that increases in soil N pool sizes and transformation rates under cheatgrass are caused by higher rates of root exudation or release of organic matter containing relatively large amounts of labile N. Our results provide the first evidence for the underlying mechanism by which the invasive annual cheatgrass increases N availability and establishes positive plant-soil feedbacks that promote its success in western rangelands. PMID:26796411

  3. New Results from the NOAA CREST Lidar Network (CLN) Observations in the US Eastcoast

    NASA Astrophysics Data System (ADS)

    Moshary, Fred; Han, Zaw; Wu, Yonghua; Gross, Barry; Wesloh, Daniel; Hoff, Raymond M.; Delgado, Ruben; Su, Jia; Lei, Liqiao; Lee, Robert B.; McCormick, M. Pat; Diaz, Jesus; Cruz, Carlos; Parsiani, Hamed

    2016-06-01

    This paper presents coordinated ground-based observations by the NOAA-CREST Lidar Network (CLN) for profiling of aerosols, cloud, water vapor, and wind along the US east coast including Caribbean region at Puerto Rico. The instrumentation, methodology and observation capability are reviewed. The applications to continental and intercontinental-scale transport of smoke and dust plumes, and their large scale regional impact are discussed.

  4. Johns Hopkins University Announces Frederick CREST Classes for Fall 2016 | Poster

    Cancer.gov

    Johns Hopkins University’s (JHU) Advanced Academic Programs (AAP) division recently announced two classes that will be hosted at the Frederick Center for Research and Education in Science and Technology (CREST) this fall. According to a JHU press release, the classes are Biochemistry, which is part of the M.S. in Biotechnology program at JHU AAP, and Molecular Biology, a part of the M.S. in Bioinformatics program at JHU AAP.

  5. Iliac crest autograft versus alternative constructs for anterior cervical spine surgery: Pros, cons, and costs

    PubMed Central

    Epstein, Nancy E.

    2012-01-01

    Background: Grafting choices available for performing anterior cervical diskectomy/fusion (ACDF) procedures have become a major concern for spinal surgeons, and their institutions. The “gold standard”, iliac crest autograft, may still be the best and least expensive grafting option; it deserves to be reassessed along with the pros, cons, and costs for alternative grafts/spacers. Methods: Although single or multilevel ACDF have utilized iliac crest autograft for decades, the implant industry now offers multiple alternative grafting and spacer devices; (allografts, cages, polyether-etherketone (PEEK) amongst others). While most studies have focused on fusion rates and clinical outcomes following ACDF, few have analyzed the “value-added” of these various constructs (e.g. safety/efficacy, risks/complications, costs). Results: The majority of studies document 95%-100% fusion rates when iliac crest autograft is utilized to perform single level ACDF (X-ray or CT confirmed at 6-12 postoperative months). Although many allograft studies similarly quote 90%-100% fusion rates (X-ray alone confirmed at 6-12 postoperative months), a recent “post hoc analysis of data from a prospective multicenter trial” (Riew KD et. al., CSRS Abstract Dec. 2011; unpublished) revealed a much higher delayed fusion rate using allografts at one year 55.7%, 2 years 87%, and four years 92%. Conclusion: Iliac crest autograft utilized for single or multilevel ACDF is associated with the highest fusion, lowest complication rates, and significantly lower costs compared with allograft, cages, PEEK, or other grafts. As spinal surgeons and institutions become more cost conscious, we will have to account for the “value added” of these increasingly expensive graft constructs. PMID:22905321

  6. Computed tomography evaluation of the iliac crest apophysis: age estimation in living individuals.

    PubMed

    Ekizoglu, Oguzhan; Inci, Ercan; Erdil, Irem; Hocaoglu, Elif; Bilgili, Mustafa Gokhan; Kazimoglu, Cemal; Reisoglu, Ali; Can, Ismail Ozgur

    2016-07-01

    Determination of the ossification properties of the iliac apophysis is important not only in the clinical evaluation of patients undergoing orthopedic surgery but also in age estimation studies for forensic purposes. The literature includes both anthropological and radiological (conventional radiography, ultrasonography, and magnetic resonance imaging modalities) investigations of the different staging systems used for these purposes. In this study, we assessed the utility of computed tomography (CT) of the iliac crest apophysis in estimating forensic age. CT scans of the iliac crest apophysis of 380 patients (187 females, 193 males, and 10-29 years of age) were evaluated according to the four-stage system. Further subclassification did not give data properly due to the reference length measurement of the iliac wing with CT. Thus, in our series, stage 2 was first seen in 12 years of age and stage 3 in those 14 years of age in both sexes and on both sides of the pelvis. Stage 4 was first seen in 17 years of both sexes but only on the right side; on the left side, it appeared in females 18 years of age and in males 17 years of age. Present data was found consistent with previous pelvic radiographic findings. First seen ages for stage 2 and 3 are 12 and 14 years respectively which presented valuable information for legally important age thresholds. However, disadvantages of CT, including high-dose radiation exposure to gonads, the difficulty of evaluating the iliac crest, and the age boundary of 17 years, could make this method infeasible, as compared with hand wrist and pelvic radiographic methods. CT of the iliac crest has probably a greater utility where preexisting CT scans of the pelvic region are available, and it may be considered as a supportive method for age-estimation purposes. PMID:26914804

  7. Isolation of Novel Multipotent Neural Crest-Derived Stem Cells from Adult Human Inferior Turbinate

    PubMed Central

    Hauser, Stefan; Widera, Darius; Qunneis, Firas; Müller, Janine; Zander, Christin; Greiner, Johannes; Strauss, Christina; Lüningschrör, Patrick; Heimann, Peter; Schwarze, Hartmut; Ebmeyer, Jörg; Sudhoff, Holger; Araúzo-Bravo, Marcos J.; Greber, Boris; Zaehres, Holm; Schöler, Hans; Kaltschmidt, Christian

    2012-01-01

    Adult human neural crest-derived stem cells (NCSCs) are of extraordinary high plasticity and promising candidates for the use in regenerative medicine. Here we describe for the first time a novel neural crest-derived stem cell population within the respiratory epithelium of human adult inferior turbinate. In contrast to superior and middle turbinates, high amounts of source material could be isolated from human inferior turbinates. Using minimally-invasive surgery methods isolation is efficient even in older patients. Within their endogenous niche, inferior turbinate stem cells (ITSCs) expressed high levels of nestin, p75NTR, and S100. Immunoelectron microscopy using anti-p75 antibodies displayed that ITSCs are of glial origin and closely related to nonmyelinating Schwann cells. Cultivated ITSCs were positive for nestin and S100 and the neural crest markers Slug and SOX10. Whole genome microarray analysis showed pronounced differences to human ES cells in respect to pluripotency markers OCT4, SOX2, LIN28, and NANOG, whereas expression of WDR5, KLF4, and c-MYC was nearly similar. ITSCs were able to differentiate into cells with neuro-ectodermal and mesodermal phenotype. Additionally ITSCs are able to survive and perform neural crest typical chain migration in vivo when transplanted into chicken embryos. However ITSCs do not form teratomas in severe combined immunodeficient mice. Finally, we developed a separation strategy based on magnetic cell sorting of p75NTR positive ITSCs that formed larger neurospheres and proliferated faster than p75NTR negative ITSCs. Taken together our study describes a novel, readily accessible source of multipotent human NCSCs for potential cell-replacement therapy. PMID:22128806

  8. Maladie thromboembolique veineuse dans la région de Sidi Bel Abbes, Algérie: fréquence et facteurs de risque

    PubMed Central

    Chalal, Nourelhouda; Demmouche, Abbassia

    2013-01-01

    Introduction La maladie thromboembolique veineuse (MTEV) présente par ses deux entités cliniques: thrombose veineuse profonde (TVP) et embolie pulmonaire (EP), est une pathologie fréquente ayant une forte morbi-mortalité. En Algérie, cette pathologie prend de plus en plus de l'ampleur, en l'absence de toute publication révélant sa fréquence et le pouvoir thrombogène des facteurs de risque qui lui sont corrélés. Notre étude a pour objectif de déterminer la fréquence et les facteurs de risque de ce type d'affection dans la région de Sidi Bel Abbes, Algérie. Méthodes Il s'agit d'une étude rétrospective allant du 1er janvier 2006 au 10 juin 2012 ciblant les patients hospitalisés pour TVP et /ou EP au sein du service de cardiologie du CHU de Sidi Bel Abbes. Résultats 183 patients atteints de la MTEV dont 112 femmes (61.2%) d’âge moyen 46.4 ± 17.9 et 71 hommes (38.7%) d’âge moyen 51.5 ± 17.7 ont été notés. 146 cas parmi eux (79.7%) présentaient une TVP isolée, alors que 37 autres (20.2%) étaient atteints d'EP, dont 16 cas de TVP associée. Les facteurs de risque les plus fréquents enregistrés en cas de TVP sont surtout: l'immobilité, l'hypertension, la chirurgie, et la contraception orale, tandis que: l'immobilité, la chirurgie, l'hypertension et les fractures sont les facteurs de risques les plus incriminés en cas d'EP. 24.7% des patients présentaient plusieurs facteurs de risque. L'antécédent personnel de la MTEV, était présent dans 12.02% des cas. 97.5% des TVP ont touché les membres inférieurs mais seulement 2.5% des TVP étaient localisés au niveau des membres supérieurs. Conclusion Au terme de notre étude, et en dépit de sa fréquence non alarmante, il serait indispensable d'envisager l'adoption d'une stratégie prophylactique adéquate afin de lutter contre le développement redoutable de ce genre d'affection dans la région de Sidi Bel Abbes. PMID:24648858

  9. Analysis of neural crest-derived clones reveals novel aspects of facial development.

    PubMed

    Kaucka, Marketa; Ivashkin, Evgeny; Gyllborg, Daniel; Zikmund, Tomas; Tesarova, Marketa; Kaiser, Jozef; Xie, Meng; Petersen, Julian; Pachnis, Vassilis; Nicolis, Silvia K; Yu, Tian; Sharpe, Paul; Arenas, Ernest; Brismar, Hjalmar; Blom, Hans; Clevers, Hans; Suter, Ueli; Chagin, Andrei S; Fried, Kaj; Hellander, Andreas; Adameyko, Igor

    2016-08-01

    Cranial neural crest cells populate the future facial region and produce ectomesenchyme-derived tissues, such as cartilage, bone, dermis, smooth muscle, adipocytes, and many others. However, the contribution of individual neural crest cells to certain facial locations and the general spatial clonal organization of the ectomesenchyme have not been determined. We investigated how neural crest cells give rise to clonally organized ectomesenchyme and how this early ectomesenchyme behaves during the developmental processes that shape the face. Using a combination of mouse and zebrafish models, we analyzed individual migration, cell crowd movement, oriented cell division, clonal spatial overlapping, and multilineage differentiation. The early face appears to be built from multiple spatially defined overlapping ectomesenchymal clones. During early face development, these clones remain oligopotent and generate various tissues in a given location. By combining clonal analysis, computer simulations, mouse mutants, and live imaging, we show that facial shaping results from an array of local cellular activities in the ectomesenchyme. These activities mostly involve oriented divisions and crowd movements of cells during morphogenetic events. Cellular behavior that can be recognized as individual cell migration is very limited and short-ranged and likely results from cellular mixing due to the proliferation activity of the tissue. These cellular mechanisms resemble the strategy behind limb bud morphogenesis, suggesting the possibility of common principles and deep homology between facial and limb outgrowth. PMID:27493992

  10. JUSTIFICATION FOR A REDUCTION IN THE CREST-STAGE GAGE PROGRAM IN LOUISIANA.

    USGS Publications Warehouse

    Herbert, Richard A.; Carlson, Darrell D.; Wiche, Gregg J.

    1985-01-01

    The crest-stage gage program in Louisiana was evaluated to determine if the data were adequate for use in developing regional flood-frequency equations and to determine if any crest-stage gage stations could be discontinued. An abundance of data at many crest-stage gage stations and a lack of data for urban areas and flat-slope areas indicated a need for a shift in the number, type, and locations of gages. Correlations and comparisons of annual peak discharges and watershed characteristics of 96 existing stations resulted in the elimination of 72 stations and the addition of one new station, reducing the total network to 25 stations that could be used for future flood-frequency analyses. The adequacy of the reduced network for development and verification of regional flood-frequency equations was tested by comparing a set of regional flood-frequency equations developed using data from the full network with a set developed using data from the reduced network.

  11. Evidence of secondary consumption of invertebrate prey by Double-crested Cormorants

    USGS Publications Warehouse

    Johnson, J.H.; Ross, R.M.; Smith, D.R.

    1997-01-01

    The piscivorous nature of the Double-crested Cormorant (Phalacrocorax auritus) is well documented. However, many researchers who have used regurgitated pellets to describe the diet of cormorants report that invertebrates compose a small but consistent portion of the diet. We examined the hypothesis that invertebrates found in pellets are primarily the result of secondary consumption. We used odds ratio analysis to examine associations in 2,846 individual pellets between the presence of specific invertebrate prey and the presence of fish species known to consume those invertebrate taxa. Significant (P < 0.05) relationships occurred between gastropods and pumpkinseed (Lepomis gibbosus) and ictalurids, and between decapods and rock bass (Ambloplites rupestris) and smallmouth bass (Micropterus dolomieu). Significant (P < 0.05) relationships were also found between pelecypods and pumpkinseed and ictalurids. We suggest that the invertebrate prey we observed in pellets were present in the digestive tracts of fish that were consumed by Double-crested Cormorants and hence represent secondary consumption by cormorants. We conclude that consumption of invertebrates by Double-crested Cormorants may be overestimated in the literature in instances where the diet was described using pellets.

  12. Use of the vascularized iliac-crest flap in musculoskeletal lesions.

    PubMed

    Tonoli, Cristiane; Bechara, Alexandre H S; Rossanez, Roberto; Belangero, William D; Livani, Bruno

    2013-01-01

    Bone loss was in the past treated by several methods, such as bone distraction and the use of nonvascularized or tissue-bank bone grafts. With the advent of modern microsurgical techniques, the vascularized bone flap has been used with good results; it resolves local nutritional problems, repairs soft tissue that is often damaged by severe trauma, and treats bone loss due to tumors, pseudarthroses, and osteomyelitis. This paper reports the authors' experience with the use of vascularized iliac-crest flaps to treat orthopedic pathologies in five patients with traumatic bone loss (<10 cm), three with osteomyelitis, and three with atrophic nonunion. In all cases, the same surgeon obtained a vascularized iliac-crest flap with a pedicle based on the deep iliac circumflex artery. All flaps consolidated within a mean period of 3 months. These findings demonstrate that the use of an iliac-crest flap is a treatment option in cases of bone loss and that it is associated with good functional results and minimal donor-site morbidity. PMID:24233062

  13. Use of the Vascularized Iliac-Crest Flap in Musculoskeletal Lesions

    PubMed Central

    Tonoli, Cristiane; Bechara, Alexandre H. S.; Rossanez, Roberto; Belangero, William D.; Livani, Bruno

    2013-01-01

    Bone loss was in the past treated by several methods, such as bone distraction and the use of nonvascularized or tissue-bank bone grafts. With the advent of modern microsurgical techniques, the vascularized bone flap has been used with good results; it resolves local nutritional problems, repairs soft tissue that is often damaged by severe trauma, and treats bone loss due to tumors, pseudarthroses, and osteomyelitis. This paper reports the authors' experience with the use of vascularized iliac-crest flaps to treat orthopedic pathologies in five patients with traumatic bone loss (<10 cm), three with osteomyelitis, and three with atrophic nonunion. In all cases, the same surgeon obtained a vascularized iliac-crest flap with a pedicle based on the deep iliac circumflex artery. All flaps consolidated within a mean period of 3 months. These findings demonstrate that the use of an iliac-crest flap is a treatment option in cases of bone loss and that it is associated with good functional results and minimal donor-site morbidity. PMID:24233062

  14. Applications of Mesenchymal Stem Cells and Neural Crest Cells in Craniofacial Skeletal Research

    PubMed Central

    Ouchi, Takehito; Shibata, Shinsuke; Fujimura, Takumi; Kawana, Hiromasa; Okano, Hideyuki; Nakagawa, Taneaki

    2016-01-01

    Craniofacial skeletal tissues are composed of tooth and bone, together with nerves and blood vessels. This composite material is mainly derived from neural crest cells (NCCs). The neural crest is transient embryonic tissue present during neural tube formation whose cells have high potential for migration and differentiation. Thus, NCCs are promising candidates for craniofacial tissue regeneration; however, the clinical application of NCCs is hindered by their limited accessibility. In contrast, mesenchymal stem cells (MSCs) are easily accessible in adults, have similar potential for self-renewal, and can differentiate into skeletal tissues, including bones and cartilage. Therefore, MSCs may represent good sources of stem cells for clinical use. MSCs are classically identified under adherent culture conditions, leading to contamination with other cell lineages. Previous studies have identified mouse- and human-specific MSC subsets using cell surface markers. Additionally, some studies have shown that a subset of MSCs is closely related to neural crest derivatives and endothelial cells. These MSCs may be promising candidates for regeneration of craniofacial tissues from the perspective of developmental fate. Here, we review the fundamental biology of MSCs in craniofacial research. PMID:27006661

  15. The positive transcriptional elongation factor (P-TEFb) is required for neural crest specification.

    PubMed

    Hatch, Victoria L; Marin-Barba, Marta; Moxon, Simon; Ford, Christopher T; Ward, Nicole J; Tomlinson, Matthew L; Desanlis, Ines; Hendry, Adam E; Hontelez, Saartje; van Kruijsbergen, Ila; Veenstra, Gert Jan C; Münsterberg, Andrea E; Wheeler, Grant N

    2016-08-15

    Regulation of gene expression at the level of transcriptional elongation has been shown to be important in stem cells and tumour cells, but its role in the whole animal is only now being fully explored. Neural crest cells (NCCs) are a multipotent population of cells that migrate during early development from the dorsal neural tube throughout the embryo where they differentiate into a variety of cell types including pigment cells, cranio-facial skeleton and sensory neurons. Specification of NCCs is both spatially and temporally regulated during embryonic development. Here we show that components of the transcriptional elongation regulatory machinery, CDK9 and CYCLINT1 of the P-TEFb complex, are required to regulate neural crest specification. In particular, we show that expression of the proto-oncogene c-Myc and c-Myc responsive genes are affected. Our data suggest that P-TEFb is crucial to drive expression of c-Myc, which acts as a 'gate-keeper' for the correct temporal and spatial development of the neural crest. PMID:27343897

  16. Minimal-resource computer program for automatic generation of ocean wave ray or crest diagrams in shoaling waters

    NASA Technical Reports Server (NTRS)

    Poole, L. R.; Lecroy, S. R.; Morris, W. D.

    1977-01-01

    A computer program for studying linear ocean wave refraction is described. The program features random-access modular bathymetry data storage. Three bottom topography approximation techniques are available in the program which provide varying degrees of bathymetry data smoothing. Refraction diagrams are generated automatically and can be displayed graphically in three forms: Ray patterns with specified uniform deepwater ray density, ray patterns with controlled nearshore ray density, or crest patterns constructed by using a cubic polynomial to approximate crest segments between adjacent rays.

  17. Profil épidémiologique des fibromes utérins dans la région de Sidi Bel Abbes, Algérie

    PubMed Central

    Chalal, Nourelhouda; Demmouche, Abbassia

    2013-01-01

    Introduction Les léiomyomes ou fibromyomes plus communément dénommés fibromes, sont les tumeurs les plus répandues du tractus génital féminin. Ils affectent 20 à 25% des femmes en activité génitale. Notre étude vise à élucider la réalité de ce type de pathologie dans la région de sidi bel Abbes, nord-ouest d'Algérie. Méthodes A travers une étude rétrospective allant du 1er janvier 2008 au 1 mai 2011 portant sur les patientes opérées pour fibrome au sein de la maternité de Sidi Bel Abbes, nous avons relevé les particularités épidémiologiques et cliniques de cette pathologie. Résultats Au total 323 cas de fibromes ont été recensés. La tranche d'âge la plus touchée varie de 40 à 44 ans dans une fourchette d'âge comprise entre 20 et 74 ans. 37.83% des patientes étaient nullipares. Une prédominance des patientes dont l'âge de la ménarche est précoce, a été retenue (60.3%). 3% des femmes ont présenté un terrain familial prédisposant. La symptomatologie était dominée par les hémorragies génitales (35%). La majorité des patientes (51.70%) présentaient un utérus polymyomateux dont la localisation des fibromes était principalement corporéale (96%), sous séreuse (43%). Le traitement était conservateur dans 71.82% des cas. Conclusion Sur la base des résultats obtenus, la mise au point d'un programme national de sensibilisation et de dépistage précoce, s'impose PMID:23847704

  18. Quantitative and qualitative morphologic, cytochemical and ultrastructural characteristics of blood cells in the Crested Serpent eagle and Shikra.

    PubMed

    Salakij, Chaleow; Kasorndorkbua, Chaiyan; Salakij, Jarernsak; Suwannasaeng, Pimsuda; Jakthong, Pattarapong

    2015-08-01

    The Crested Serpent eagle (Spilornis cheela) is a bird of prey found in the tropical rain forest in Thailand. The Shikra (Accipiter badius) is a sparrow hawk and common resident in Thailand. Blood samples from 9 Crested Serpent eagles and 12 Shikras were obtained from September 2010 to November 2014. They were clinically healthy and negative for blood parasites detectable by light microscopy and molecular techniques (partial cytochrome b gene for avian malaria and partial 18S rRNA gene for trypanosome). Cytochemical staining (Sudan black B, peroxidase, α-naphthyl acetate esterase, and β-glucuronidase) and transmission electron microscopy were performed. Hematological results were reported as the mean ± standard deviation and median. Heterophils were the most prevalent leukocytes in the Crested Serpent eagle, but in the Shikra, lymphocytes were the most prevalent leukocytes. In the Shikra, some vacuoles were observed in the cytoplasm of the eosinophils. All blood cells in both types of raptors stained positively for β-glucuronidase but negatively for peroxidase. The ultrastructure of heterophils showed more clearly differentiate long rod granules in Crested Serpent eagle and spindle-shaped granules in Shikra. The ultrastructure of the eosinophils in the Crested Serpent eagle revealed varied electron-dense, round-shaped granules with round, different electron-dense areas in the centers of some granules, which differed from the structure reported for other raptors. These quantitative results may be useful for clinical evaluations of Crested Serpent eagles and Shikras that are undergoing rehabilitation for release. PMID:26563029

  19. Inactivation of Geminin in neural crest cells affects the generation and maintenance of enteric progenitor cells, leading to enteric aganglionosis.

    PubMed

    Stathopoulou, Athanasia; Natarajan, Dipa; Nikolopoulou, Pinelopi; Patmanidi, Alexandra L; Lygerou, Zoi; Pachnis, Vassilis; Taraviras, Stavros

    2016-01-15

    Neural crest cells comprise a multipotent, migratory cell population that generates a diverse array of cell and tissue types, during vertebrate development. Enteric Nervous System controls the function of the gastrointestinal tract and is mainly derived from the vagal and sacral neural crest cells. Deregulation on self-renewal and differentiation of the enteric neural crest cells is evident in enteric nervous system disorders, such as Hirschsprung disease, characterized by the absence of ganglia in a variable length of the distal bowel. Here we show that Geminin is essential for Enteric Nervous System generation as mice that lacked Geminin expression specifically in neural crest cells revealed decreased generation of vagal neural crest cells, and enteric neural crest cells (ENCCs). Geminin-deficient ENCCs showed increased apoptosis and decreased cell proliferation during the early stages of gut colonization. Furthermore, decreased number of committed ENCCs in vivo and the decreased self-renewal capacity of enteric progenitor cells in vitro, resulted in almost total aganglionosis resembling a severe case of Hirschsprung disease. Our results suggest that Geminin is an important regulator of self-renewal and survival of enteric nervous system progenitor cells. PMID:26658318

  20. Changes in volume during the four months' remodelling period of iliac crest grafts in reconstruction of the alveolar ridge.

    PubMed

    Dreiseidler, Timo; Kaunisaho, Veronika; Neugebauer, Jörg; Zöller, Joachim E; Rothamel, Daniel; Kreppel, Matthias

    2016-09-01

    Our aim was to assess the four months' resorption rates of onlay iliac crest grafts in atrophic jaws prospectively, and to identify factors that influence them. Twenty-four patients had reconstructions of the alveolar ridge with iliac crest onlay grafts at 30 sites on the mandibles and maxillas. The augmentation volumes were measured on cone-beam computed tomographic (CT) data-sets directly after augmentation (V1), and after four months' remodelling (V2). Statistical analysis allowed identification of potential influences from the recipient sites, volume of the graft, and the patients' smoking behaviour. The mean (range) initial onlay graft volume (V1) was 2.82 (0.66 to 6.41) ml. After four months, the mean measured onlay graft volume (V2) was 2.39 (0.47 to 6.21) ml. Mean iliac crest onlay graft volume resorption after four months of remodelling was 0.43 (-0.15 - 1.78) ml (15%). We found no significant differences in the resorption rates of iliac crest onlay grafts between different recipient sites (maxilla and mandible) or in dependence on the volume of iliac crest grafts. Smokers tended to have a higher rate of resorption, but not significantly so (p=0.056). The results of this study indicate the most favourable resorption rates for iliac crest onlay grafts that we know have seen published to date. PMID:27185231

  1. Final Report-Confirmatory Survey Results for the ABB Combustion Engineering Site, Windsor, Connecticut; Revision 1 (DCN 5158-SR-02-1) (Docket No. 030-03754; RFTA No. 12-003)

    SciTech Connect

    ADAMS, WADE C

    2013-01-28

    The objectives of the confirmatory activities were to provide independent contractor field data reviews and to generate independent radiological data for use by the NRC in evaluating the adequacy and accuracy of the contractor's procedures and FSS results. ORAU reviewed ABB CE's decommissioning plan, final status survey plan, and the applicable soil DCGLs, which were developed based on an NRC-approved radiation dose assessment. The surveys included gamma surface scans, gamma direct measurements, and soil sampling.

  2. Comparative osteogenesis of maxilla and iliac crest human bone marrow stromal cells attached to oxidized titanium - a pilot study

    PubMed Central

    Akintoye, Sunday O; Giavis, Parascevi; Stefanik, Derek; Levin, Lawrence; Mante, Francis K

    2010-01-01

    Objectives Severe alveolar bone loss affects dental implant placement. Bone augmentation by grafting iliac crest bone rich in osteoprogenitor cells like bone marrow stromal cells (BMSCs) requires a second surgical procedure in non-orofacial bone. Skeletal site-specific osteogenesis indicates maxilla and mandible BMSCs are highly proliferative and exhibit osteogenic properties superior to iliac crest BMSCs. Alveolar bone can be easily obtained during routine dental surgery, but it is unclear if titanium-attached alveolar BMSCs will retain their superior osteogenic properties. This study evaluated and compared in vitro osteogenic properties of titanium-attached maxilla and iliac crest BMSCs in same individuals. Materials and Methods Primary culture of maxilla and iliac crest BMSCs from four normal healthy volunteers were expanded in culture. In 24-well plates, first passage BMSCs were seeded directly (1 × 104 cells/well) on oxidized titanium discs (1.27cm diameter and 2mm thickness) or tissue culture plate. Each cell type was assessed for affinity for titanium, post-attachment survival and osteogenic differentiation based on alkaline phosphatase and osteopontin expressions. Results There was no difference in the affinity of maxilla and iliac crest BMSCs to titanium. However, titanium-attached maxilla BMSCs were apparently more osteogenically responsive than iliac crest cells based on calcium accumulation and gene expression of alkaline phosphatase and osteopontin. But these differences were not statistically significant in this small patient sample. Conclusion Maxilla and iliac crest BMSCs have similar attachment affinity for titanium. This pilot study indicate that titanium-attached maxilla BMSCs were more osteogenically responsive and may be a viable and more readily available donor graft material in implant dentistry. PMID:18983324

  3. Iliac crest allograft glenoid reconstruction for recurrent anterior shoulder instability in athletes: Surgical technique and results

    PubMed Central

    Mascarenhas, Randy; Raleigh, Eden; McRae, Sheila; Leiter, Jeff; Saltzman, Bryan; MacDonald, Peter B.

    2014-01-01

    Performing a labral repair alone in patients with recurrent anterior instability and a large glenoid defect has led to poor outcomes. We present a technique involving the use of the iliac crest allograft inserted into the glenoid defect in athletes with recurrent anterior shoulder instability and large bony defects of the glenoid (>25% of glenoid diameter). All athletes with recurrent anterior shoulder instability and a large glenoid defect that underwent open anterior shoulder stabilization and glenoid reconstruction with the iliac crest allograft were followed over a 4-year period. Preoperatively, a detailed history and physical exam were obtained along with standard radiographs and magnetic resonance imaging of the affected shoulder. All patients also completed the Simple Shoulder Test (SST) and American Shoulder and Elbow Surgeons (ASES) evaluation forms preoperatively. A computed tomography scan was obtained postoperatively to assess osseous union of the graft and the patient again went through a physical exam in addition to completing the SST, ASES, and Western Ontario Shoulder Instability Index (WOSI) forms. 10 patients (9 males, 1 female) were followed for an average of 16 months (4–36 months) and had a mean age of 24.4 years. All patients exhibited a negative apprehension/relocation test and full shoulder strength at final follow-up. Eight of 10 patients had achieved osseous union at 6 months (80.0%). ASES scores improved from 64.3 to 97.8, and SST scores improved from 66.7 to 100. Average postoperative WOSI scores were 93.8%. The use of the iliac crest allograft provides a safe and clinically useful alternative compared to previously described procedures for recurrent shoulder instability in the face of glenoid deficiency. PMID:25538432

  4. Role of Free Iliac Crest Flap in Foot and Ankle Reconstruction.

    PubMed

    Repo, Jussi Petteri; Barner-Rasmussen, Ian; Roine, Risto P; Sintonen, Harri; Tukiainen, Erkki

    2016-06-01

    Background Reconstruction of extensive bone and compound defects in the foot and ankle is challenging. This cross-sectional study aimed to assess the outcomes of free iliac crest flap in foot and ankle reconstruction. Methods We retrospectively reviewed patient records and identified 13 cases with 1 osseous and 12 composite free iliac crest grafts for compound fracture (n = 3) or sequelae (n = 10) in the foot and ankle. We applied the visual analogue scale foot and ankle, the Oswestry disability index, and the 15D health-related quality of life (HRQoL) instruments. Results The average follow-up period was 3.9 years (range, 1.3-8.0 years). Four patients underwent early reoperations; venous and arterial reanastomosis (n = 1), minor wound revision (n = 2), or flap reconstruction due to partial necrosis of the skin island (n = 1). The median time to bone union was 23 months (range, 7-46 months). One permanent pseudoarthrosis occurred. One patient underwent late below-knee amputation due to chronic pain and functional impairment. One patient required flap reconstruction due to a late donor-site defect. Seven patients completed the questionnaires on an average of 14.7 years postoperatively (range, 2.0-26.9 years). Noted impairment of the donor site and of the reconstructed limb ranged from none to significant. Five (out of seven) patients had a HRQoL comparable to that of an age-standardized general population. Conclusions The free iliac crest flap is a feasible option for extensive compound fractures and bone-healing complications in the foot and ankle. It can also be used to achieve ankle arthrodesis when other techniques have failed and in patients at high risk for amputation. PMID:26848564

  5. Organochlorine contaminants in bald eagles and double-crested cormorants nesting along the lower Columbia River

    SciTech Connect

    Buck, J.; Schuler, C.; Anthony, R.; Tillitt, D.

    1995-12-31

    The Columbia River receives numerous contaminants from municipal and industrial permitted discharges, nonpoint pollution, accidental spills, and hazardous waste sites. Poor reproductive success has been documented in bald eagles (Haliaeetus leucocephalus) nesting along the river, and concentrations of DDE and PCBs in eagle eggs has been correlated with reduced productivity and significant eggshell thinning. Recently, elevated 2,3,7,8 tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) concentrations also were detected in embryos of bald eagles and double-crested cormorants. The authors collected eggs from 11 bald eagle nest sites in 1994 and from 10 cormorant nest sites in 1993 and 1994 and found organochlorines at concentrations potentially harmful to the species. DDE, PCBS, and 2,3,7,8-TCDD in bald eagle eggs averaged 6.84 parts per million (ppm), 6.15 ppm, and 30 parts per trillion (pptr)fresh weight, respectively. In cormorant eggs, fresh weight values ranged from 1.14 to 13.1 ppm for DDE, 0.98 to 9.67 for total PCBS, and 4.8 to 58 pptr for 2,3,7,8-TCDD. Cormorant eggs subjected to a H4IIE rat hepatoma cell bioassay indicated the amounts of TCDD-Equivalents (TCDD-EQs) present would relate to a 23% egg mortality when compared to dose-response relationships between H4IIE-derived TCDD-EQs and egg mortality rates in double-crested cormorants in the Great Lakes. Preliminary results suggest DDE continues to impair reproductive success in Columbia River bald eagles, and dioxin and PCB concentrations may be impacting double-crested cormorants. Further egg analysis and productivity studies will be conducted in 1995.

  6. Comparison of NOAA-CREST Soil Moisture Measurements with SMOS Products

    NASA Astrophysics Data System (ADS)

    Norouzi, H.; Forbes, A.

    2014-12-01

    In October 2014, the Soil Moisture Active and Passive mission (SMAP) will launch into a near-polar and sun- synchronous orbit. SMAP includes the first 3 KM resolution product, by both radar and radiometer sensors which will transmit useful information concentrating on the global measurements of soil moisture and freeze/thaw cycles. NOAA- CREST (National Oceanic and Atmospheric Administration- Cooperative Remote Sensing Science and Technology) deploys a series of in-situ devices into the soil, and an L-BAND Radiometer close to the site ground at the Cary Institute in Millbrook, NY. The site is important for future validation of SMAP mission. Comparing mathematical and ground based remote sensing of soil moisture is beneficial to ensure the accuracy of the measurements. The focus of this research is to analyze and compare soil moisture from ESA- SMOS (Europe Space Agency- Soil Moisture Ocean Salinity) mission and the Cary Institute's soil moisture measurements within the same time period, and location. In the interest of establishing superb authentication; comparing SMOS and ground measurements will justify the accuracy of the newly launch satellite. Discrepancies can be found between field point measurement and relatively large footprint of SMOS, which affects comparison and validation. Several techniques and statistical methods will provide a more meaningful comparison to analyze soil moisture data. The results of this project will help to provide a useful method to compare the NOAA-CREST soil moisture measurements and SMAP measurements. In conclusion, the SMAP advance technology will provide more accurate feedback for modeling numerical weather and climate models. Keywords: Soil Moisture, Precipitation, CREST-SMART, Cary Institute, In-situ, Remote Sensors Accurate Soil Moisture Data, Millbrook, N.Y., CATDS, Hydrology is the branch of science concerning properties of earth's water especially its movement in relation to land. SMOS MIRAS, SMAP, Sensors (Underground)

  7. Odd-skipped related-1 controls neural crest chondrogenesis during tongue development

    PubMed Central

    Liu, Han; Lan, Yu; Xu, Jingyue; Chang, Ching-Fang; Brugmann, Samantha A.; Jiang, Rulang

    2013-01-01

    The tongue is a critical element of the feeding system in tetrapod animals for their successful adaptation to terrestrial life. Whereas the oral part of the mammalian tongue contains soft tissues only, the avian tongue has an internal skeleton extending to the anterior tip. The mechanisms underlying the evolutionary divergence in tongue skeleton formation are completely unknown. We show here that the odd-skipped related-1 (Osr1) transcription factor is expressed throughout the neural crest-derived tongue mesenchyme in mouse, but not in chick, embryos during early tongue morphogenesis. Neural crest-specific inactivation of Osr1 resulted in formation of an ectopic cartilage in the mouse tongue, reminiscent in shape and developmental ontogeny of the anterior tongue cartilage in chick. SRY-box containing gene-9 (Sox9), the master regulator of chondrogenesis, is widely expressed in the nascent tongue mesenchyme at the onset of tongue morphogenesis but its expression is dramatically down-regulated concomitant with activation of Osr1 expression in the developing mouse tongue. In Osr1 mutant mouse embryos, expression of Sox9 persisted in the developing tongue mesenchyme where chondrogenesis is subsequently activated to form the ectopic cartilage. Furthermore, we show that Osr1 binds to the Sox9 gene promoter and that overexpression of Osr1 suppressed expression of endogenous Sox9 mRNAs and Sox9 promoter-driven reporter. These data indicate that Osr1 normally prevents chondrogenesis in the mammalian tongue through repression of Sox9 expression and suggest that changes in regulation of Osr1 expression in the neural crest-derived tongue mesenchyme underlie the evolutionary divergence of birds from other vertebrates in tongue morphogenesis. PMID:24167250

  8. Odd-skipped related-1 controls neural crest chondrogenesis during tongue development.

    PubMed

    Liu, Han; Lan, Yu; Xu, Jingyue; Chang, Ching-Fang; Brugmann, Samantha A; Jiang, Rulang

    2013-11-12

    The tongue is a critical element of the feeding system in tetrapod animals for their successful adaptation to terrestrial life. Whereas the oral part of the mammalian tongue contains soft tissues only, the avian tongue has an internal skeleton extending to the anterior tip. The mechanisms underlying the evolutionary divergence in tongue skeleton formation are completely unknown. We show here that the odd-skipped related-1 (Osr1) transcription factor is expressed throughout the neural crest-derived tongue mesenchyme in mouse, but not in chick, embryos during early tongue morphogenesis. Neural crest-specific inactivation of Osr1 resulted in formation of an ectopic cartilage in the mouse tongue, reminiscent in shape and developmental ontogeny of the anterior tongue cartilage in chick. SRY-box containing gene-9 (Sox9), the master regulator of chondrogenesis, is widely expressed in the nascent tongue mesenchyme at the onset of tongue morphogenesis but its expression is dramatically down-regulated concomitant with activation of Osr1 expression in the developing mouse tongue. In Osr1 mutant mouse embryos, expression of Sox9 persisted in the developing tongue mesenchyme where chondrogenesis is subsequently activated to form the ectopic cartilage. Furthermore, we show that Osr1 binds to the Sox9 gene promoter and that overexpression of Osr1 suppressed expression of endogenous Sox9 mRNAs and Sox9 promoter-driven reporter. These data indicate that Osr1 normally prevents chondrogenesis in the mammalian tongue through repression of Sox9 expression and suggest that changes in regulation of Osr1 expression in the neural crest-derived tongue mesenchyme underlie the evolutionary divergence of birds from other vertebrates in tongue morphogenesis. PMID:24167250

  9. Myocardial function and perfusion in the CREST syndrome variant of progressive systemic sclerosis. Exercise radionuclide evaluation and comparison with diffuse scleroderma

    SciTech Connect

    Follansbee, W.P.; Curtiss, E.I.; Medsger, T.A. Jr.; Owens, G.R.; Steen, V.D.; Rodnan, G.P.

    1984-09-01

    Myocardial function and perfusion were evaluated in 22 patients with progressive systemic sclerosis with the CREST syndrome using exercise and radionuclide techniques, pulmonary function testing, and chest roentgenography. The results were compared with a similar study of 26 patients with progressive systemic sclerosis with diffuse scleroderma. The prevalence of thallium perfusion abnormalities was similar in the groups with CREST syndrome and diffuse scleroderma, (64 percent versus 77 percent), but the defects were significantly smaller in the CREST syndrome (p less than 0.01). Reperfusion thallium defects in the absence of extramural coronary artery disease were seen in 38 percent of patients with diffuse scleroderma. This finding was not seen in any of the patients with the CREST syndrome. In diffuse scleroderma, abnormalities of both right and left ventricular function were related to larger thallium perfusion defects. In the CREST syndrome, abnormalities of left ventricular function were minor, were seen only during exercise, and were unrelated to thallium perfusion defects. Abnormal resting right ventricular function was seen in 36 percent of the patients with the CREST syndrome and was associated with an isolated decrease in diffusing capacity of carbon monoxide. It is concluded that the cardiac manifestations of the CREST syndrome are distinct from those found in diffuse scleroderma. Unlike diffuse scleroderma, abnormalities of left ventricular function in the CREST syndrome are minor and are unrelated to abnormalities of coronary perfusion. Right ventricular dysfunction in the CREST syndrome appears to be primarily related to pulmonary vascular disease.

  10. Endothelin signaling activates Mef2c expression in the neural crest through a MEF2C-dependent positive-feedback transcriptional pathway.

    PubMed

    Hu, Jianxin; Verzi, Michael P; Robinson, Ashley S; Tang, Paul Ling-Fung; Hua, Lisa L; Xu, Shan-Mei; Kwok, Pui-Yan; Black, Brian L

    2015-08-15

    Endothelin signaling is essential for neural crest development, and dysregulated Endothelin signaling is associated with several neural crest-related disorders, including Waardenburg and other syndromes. However, despite the crucial roles of this pathway in neural crest development and disease, the transcriptional effectors directly activated by Endothelin signaling during neural crest development remain incompletely elucidated. Here, we establish that the MADS box transcription factor MEF2C is an immediate downstream transcriptional target and effector of Endothelin signaling in the neural crest. We show that Endothelin signaling activates Mef2c expression in the neural crest through a conserved enhancer in the Mef2c locus and that CRISPR-mediated deletion of this Mef2c neural crest enhancer from the mouse genome abolishes Endothelin induction of Mef2c expression. Moreover, we demonstrate that Endothelin signaling activates neural crest expression of Mef2c by de-repressing MEF2C activity through a Calmodulin-CamKII-histone deacetylase signaling cascade. Thus, these findings identify a MEF2C-dependent, positive-feedback mechanism for Endothelin induction and establish MEF2C as an immediate transcriptional effector and target of Endothelin signaling in the neural crest. PMID:26160899

  11. A career at the interface of cell and developmental biology: a view from the crest

    PubMed Central

    Bronner, Marianne E.

    2012-01-01

    Just as neural crest cells migrate great distances through the embryo, my journey has taken me from a childhood in a distant land to a career as a biologist. My mentoring relationships have shaped not only the careers of my trainees, but also the trajectory of my own science. One of the most satisfying aspects of mentoring comes from helping to empower the next generation of scientists to do more tomorrow than is possible today. This, together with a passion for discovery and learning new things, motivates me and makes science such a rewarding career. PMID:23112224

  12. A career at the interface of cell and developmental biology: a view from the crest.

    PubMed

    Bronner, Marianne E

    2012-11-01

    Just as neural crest cells migrate great distances through the embryo, my journey has taken me from a childhood in a distant land to a career as a biologist. My mentoring relationships have shaped not only the careers of my trainees, but also the trajectory of my own science. One of the most satisfying aspects of mentoring comes from helping to empower the next generation of scientists to do more tomorrow than is possible today. This, together with a passion for discovery and learning new things, motivates me and makes science such a rewarding career. PMID:23112224

  13. Assessment and Surgical Treatment of Calcinosis of the Shoulder Associated with CREST Syndrome

    PubMed Central

    Breusch, S. J.

    2016-01-01

    We report an unusual case of a 65-year-old lady with CREST syndrome with multiple upper and lower limb calcinosis, who presented with severe shoulder pain and stiffness, with widespread intra- and extra-articular calcinosis, which was refractory to conservative measures. We were able to identify the main cause of her symptoms through serial diagnostic injections as calcific biceps tendinosis. We will discuss her assessment and surgical management and the pathophysiology and various treatment modalities for managing the soft tissue calcinosis in rheumatological diseases. PMID:27437158

  14. Resection of sphenoidal crest, orbit and infratemporal fossa communicative meningioma through fronto-tempo-preauricular approach

    NASA Astrophysics Data System (ADS)

    Wu, Yue; Song, Xueming; An, Yihua; Hu, Shaoshan; Shi, Huaizhang; Wu, Huailan; Yang, Guoming; Cao, Xiangyi

    1999-09-01

    We reported our experience using diode laser under microscope to resect a sphenoidal crest, orbit and infratemporal fossa communicative meningioma through fronto-tempo-preauricular approach. We used contacting, un-contacting and inserting methods and the power was in the range of 5 - 30 watt. The tumor was totally removed and the patient received radiotherapy post- operation. Follow up showed that the patient survived for two years after operation. The result showed that combination of laser application during surgery and radiotherapy post-operation was an effective method to delay or prevent tumor recurrence.

  15. In vitro differentiation of quail neural crest cells into sensory-like neuroblasts

    NASA Technical Reports Server (NTRS)

    Sieber-Blum, Maya; Kumar, Sanjiv R.; Riley, Danny A.

    1988-01-01

    Data are presented that demonstrate the ability of quail neural-crest embrionic cells grown as primary culture to differentiate in vitro into sensorylike neuroblasts. After 7-14 days of growth as primary culture, many of the putative sensory neuroblasts displayed substance P (SP)-like immunoreactivity and some exhibited histochemical carbonic anhydrase activity. Double staining experiments showed that the SP-like immunoreactive neuroblasts did not contain detectable levels of tyrosine hydroxylase or dopamine-beta-hydroxylase. The neuronal nature of the cultured sensorylike neuroblasts was further documented by double labeling for antibodies against the 68 kDa neurofilament polypeptide and substance P.

  16. Restenosis after carotid artery stenting and endarterectomy: a secondary analysis of CREST, a randomised controlled trial

    PubMed Central

    Lal, Brajesh K.; Beach, Kirk W.; Roubin, Gary S.; Lutsep, Helmi L.; Moore, Wesley S.; Malas, Mahmoud B.; Chiu, David; Gonzales, Nicole R.; Burke, J. Lee; Rinaldi, Michael; Elmore, James R.; Weaver, Fred A.; Narins, Craig R.; Foster, Malcolm; Hodgson, Kim J.; Shepard, Alexander D.; Meschia, James F.; Bergelin, Robert O.; Voeks, Jenifer H.; Howard, George; Brott, Thomas G.

    2012-01-01

    Background In the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST), the composite primary endpoint of stroke, myocardial infarction, or death during the periprocedural period or ipsilateral stroke thereafter did not differ between carotid artery stenting and carotid endarterectomy for symptomatic or asymptomatic carotid stenosis. A secondary aim of this randomised trial was to compare the composite endpoint of restenosis or occlusion. Methods Patients with stenosis of the carotid artery who were asymptomatic or had had a transient ischaemic attack, amaurosis fugax, or a minor stroke were eligible for CREST and were enrolled at 117 clinical centres in the USA and Canada between Dec 21, 2000, and July 18, 2008. In this secondary analysis, the main endpoint was a composite of restenosis or occlusion at 2 years. Restenosis and occlusion were assessed by duplex ultrasonography at 1, 6, 12, 24, and 48 months and were defined as a reduction in diameter of the target artery of at least 70%, diagnosed by a peak systolic velocity of at least 3·0 m/s. Studies were done in CREST-certified laboratories and interpreted at the Ultrasound Core Laboratory (University of Washington). The frequency of restenosis was calculated by Kaplan-Meier survival estimates and was compared during a 2-year follow-up period. We used proportional hazards models to assess the association between baseline characteristics and risk of restenosis. Analyses were per protocol. CREST is registered with ClinicalTrials.gov, number NCT00004732. Findings 2191 patients received their assigned treatment within 30 days of randomisation and had eligible ultrasonography (1086 who had carotid artery stenting, 1105 who had carotid endarterectomy). In 2 years, 58 patients who underwent carotid artery stenting (Kaplan-Meier rate 6·0%) and 62 who had carotid endarterectomy (6·3%) had restenosis or occlusion (hazard ratio [HR] 0·90, 95% CI 0·63–1·29; p=0·58). Female sex (1·79, 1·25–2

  17. Meis3 is required for neural crest invasion of the gut during zebrafish enteric nervous system development

    PubMed Central

    Uribe, Rosa A.; Bronner, Marianne E.

    2015-01-01

    During development, vagal neural crest cells fated to contribute to the enteric nervous system migrate ventrally away from the neural tube toward and along the primitive gut. The molecular mechanisms that regulate their early migration en route to and entry into the gut remain elusive. Here we show that the transcription factor meis3 is expressed along vagal neural crest pathways. Meis3 loss of function results in a reduction in migration efficiency, cell number, and the mitotic activity of neural crest cells in the vicinity of the gut but has no effect on neural crest or gut specification. Later, during enteric nervous system differentiation, Meis3-depleted embryos exhibit colonic aganglionosis, a disorder in which the hindgut is devoid of neurons. Accordingly, the expression of Shh pathway components, previously shown to have a role in the etiology of Hirschsprung’s disease, was misregulated within the gut after loss of Meis3. Taken together, these findings support a model in which Meis3 is required for neural crest proliferation, migration into, and colonization of the gut such that its loss leads to severe defects in enteric nervous system development. PMID:26354419

  18. An amphioxus winged helix/forkhead gene, AmphiFoxD: insights into vertebrate neural crest evolution

    NASA Technical Reports Server (NTRS)

    Yu, Jr-Kai; Holland, Nicholas D.; Holland, Linda Z.

    2002-01-01

    During amphioxus development, the neural plate is bordered by cells expressing many genes with homologs involved in vertebrate neural crest induction. However, these amphioxus cells evidently lack additional genetic programs for the cell delaminations, migrations, and differentiations characterizing definitive vertebrate neural crest. We characterize an amphioxus winged helix/forkhead gene (AmphiFoxD) closely related to vertebrate FoxD genes. Phylogenetic analysis indicates that the AmphiFoxD is basal to vertebrate FoxD1, FoxD2, FoxD3, FoxD4, and FoxD5. One of these vertebrate genes (FoxD3) consistently marks neural crest during development. Early in amphioxus development, AmphiFoxD is expressed medially in the anterior neural plate as well as in axial (notochordal) and paraxial mesoderm; later, the gene is expressed in the somites, notochord, cerebral vesicle (diencephalon), and hindgut endoderm. However, there is never any expression in cells bordering the neural plate. We speculate that an AmphiFoxD homolog in the common ancestor of amphioxus and vertebrates was involved in histogenic processes in the mesoderm (evagination and delamination of the somites and notochord); then, in the early vertebrates, descendant paralogs of this gene began functioning in the presumptive neural crest bordering the neural plate to help make possible the delaminations and cell migrations that characterize definitive vertebrate neural crest. Copyright 2002 Wiley-Liss, Inc.

  19. Neural crest requires Impdh2 for development of the enteric nervous system, great vessels, and craniofacial skeleton.

    PubMed

    Lake, Jonathan I; Avetisyan, Marina; Zimmermann, Albert G; Heuckeroth, Robert O

    2016-01-01

    Mutations that impair the proliferation of enteric neural crest-derived cells (ENCDC) cause Hirschsprung disease, a potentially lethal birth defect where the enteric nervous system (ENS) is absent from distal bowel. Inosine 5' monophosphate dehydrogenase (IMPDH) activity is essential for de novo GMP synthesis, and chemical inhibition of IMPDH induces Hirschsprung disease-like pathology in mouse models by reducing ENCDC proliferation. Two IMPDH isoforms are ubiquitously expressed in the embryo, but only IMPDH2 is required for life. To further understand the role of IMPDH2 in ENS and neural crest development, we characterized a conditional Impdh2 mutant mouse. Deletion of Impdh2 in the early neural crest using the Wnt1-Cre transgene produced defects in multiple neural crest derivatives including highly penetrant intestinal aganglionosis, agenesis of the craniofacial skeleton, and cardiac outflow tract and great vessel malformations. Analysis using a Rosa26 reporter mouse suggested that some or all of the remaining ENS in Impdh2 conditional-knockout animals was derived from cells that escaped Wnt1-Cre mediated DNA recombination. These data suggest that IMPDH2 mediated guanine nucleotide synthesis is essential for normal development of the ENS and other neural crest derivatives. PMID:26546974

  20. Twist1 Controls a Cell-Specification Switch Governing Cell Fate Decisions within the Cardiac Neural Crest

    PubMed Central

    Vincentz, Joshua W.; Firulli, Beth A.; Lin, Andrea; Spicer, Douglas B.; Howard, Marthe J.; Firulli, Anthony B.

    2013-01-01

    Neural crest cells are multipotent progenitor cells that can generate both ectodermal cell types, such as neurons, and mesodermal cell types, such as smooth muscle. The mechanisms controlling this cell fate choice are not known. The basic Helix-loop-Helix (bHLH) transcription factor Twist1 is expressed throughout the migratory and post-migratory cardiac neural crest. Twist1 ablation or mutation of the Twist-box causes differentiation of ectopic neuronal cells, which molecularly resemble sympathetic ganglia, in the cardiac outflow tract. Twist1 interacts with the pro-neural factor Sox10 via its Twist-box domain and binds to the Phox2b promoter to repress transcriptional activity. Mesodermal cardiac neural crest trans-differentiation into ectodermal sympathetic ganglia-like neurons is dependent upon Phox2b function. Ectopic Twist1 expression in neural crest precursors disrupts sympathetic neurogenesis. These data demonstrate that Twist1 functions in post-migratory neural crest cells to repress pro-neural factors and thereby regulate cell fate determination between ectodermal and mesodermal lineages. PMID:23555309

  1. Genetics and evolution of plumage color in Crested Ibis: Analysis of the melanocortin-1 receptor (MC1R).

    PubMed

    Yang, J; Liu, X; Zhang, J; Qing, B; Lu, B

    2015-01-01

    The melanocortin-1-recepter gene (MC1R), an important regulator in melanin synthesis, may cause different plumage color patterns in birds: gain-of-function mutations lead to the synthesis of eumelanin, whereas loss-of-function mutations help to generate pheomelanin synthesis. We had chosen MC1R as a candidate gene for the depigmentation of crested ibis, cloned and sequenced the crested ibis MC1R gene the first time. The crested ibis MC1R sequence, highly conserved with other birds during evolution, had seven transmembrane domains which played an indispensable function through evolution. We did not found any substitution on this sequence among all the sample individuals. The phylogenetic tree showed that crested ibis separated early in the evolution of birds. TYR, TYRP1, TYRP2 and MC1R were expressed in blood and the expression of the four genes showed no significant difference (p>0.05) between normal and albinism individuals, and this result demonstrated that melanic pigments are not involved in the production of red pigmentation in birds. Further study of the crested ibis albinism should focus on analyzing carotenoid-based genes. PMID:26314199

  2. Canonical Wnt activity regulates trunk neural crest delamination linking BMP/noggin signaling with G1/S transition.

    PubMed

    Burstyn-Cohen, Tal; Stanleigh, Jonathan; Sela-Donenfeld, Dalit; Kalcheim, Chaya

    2004-11-01

    Delamination of premigratory neural crest cells depends on a balance between BMP/noggin and on successful G1/S transition. Here, we report that BMP regulates G1/S transition and consequent crest delamination through canonical Wnt signaling. Noggin overexpression inhibits G1/S transition and blocking G1/S abrogates BMP-induced delamination; moreover, transcription of Wnt1 is stimulated by BMP and by the developing somites, which concomitantly inhibit noggin production. Interfering with beta-catenin and LEF/TCF inhibits G1/S transition, neural crest delamination and transcription of various BMP-dependent genes, which include Cad6B, Pax3 and Msx1, but not that of Slug, Sox9 or FoxD3. Hence, we propose that developing somites inhibit noggin transcription in the dorsal tube, resulting in activation of BMP and consequent Wnt1 production. Canonical Wnt signaling in turn stimulates G1/S transition and generation of neural crest cell motility independently of its proposed role in earlier neural crest specification. PMID:15456730

  3. Comparison of Morbidity and Complications of Harvesting Bone from the Iliac Crest and Calvarium: A Retrospective Study

    PubMed Central

    Riachi, Fawzi; Naaman, Nada; Tabarani, Carine; Berberi, Antoine; Salameh, Ziad

    2014-01-01

    Background: The aim of this retrospective clinical study was to compare the complications after the harvest of bone from the iliac crest and the calvarium. Materials and Methods: One hundred and eighty patients were selected for this study (125 iliac crest and 55 calvarium donor sites). Data were collected from the medical records and classified as major or minor complications for each procedure. Results: The highest percentage of total complications (66.4%) was recorded when the iliac crest was harvested. The highest percentage of major complications was associated with the harvest of calvarium site (14.5%), while highest percentage of minor complications was associated with the harvest of the iliac site (60.8%). Conclusion: Harvesting of the iliac crest was associated with the highest percentage of complications. Major complications were more observed with harvesting of the calvarium. How to cite the article: Riachi F, Naaman N, Tabarani C, Berberi A, Salameh Z. Comparison of morbidity and complications of harvesting bone from the iliac crest and calvarium: A retrospective study. J Int Oral Health 2014;6(3):32-5. PMID:25083030

  4. Meis3 is required for neural crest invasion of the gut during zebrafish enteric nervous system development.

    PubMed

    Uribe, Rosa A; Bronner, Marianne E

    2015-11-01

    During development, vagal neural crest cells fated to contribute to the enteric nervous system migrate ventrally away from the neural tube toward and along the primitive gut. The molecular mechanisms that regulate their early migration en route to and entry into the gut remain elusive. Here we show that the transcription factor meis3 is expressed along vagal neural crest pathways. Meis3 loss of function results in a reduction in migration efficiency, cell number, and the mitotic activity of neural crest cells in the vicinity of the gut but has no effect on neural crest or gut specification. Later, during enteric nervous system differentiation, Meis3-depleted embryos exhibit colonic aganglionosis, a disorder in which the hindgut is devoid of neurons. Accordingly, the expression of Shh pathway components, previously shown to have a role in the etiology of Hirschsprung's disease, was misregulated within the gut after loss of Meis3. Taken together, these findings support a model in which Meis3 is required for neural crest proliferation, migration into, and colonization of the gut such that its loss leads to severe defects in enteric nervous system development. PMID:26354419

  5. Fgf20b is required for the ectomesenchymal fate establishment of cranial neural crest cells in zebrafish

    SciTech Connect

    Yamauchi, Hajime; Goto, Mami; Katayama, Mika; Miyake, Ayumi; Itoh, Nobuyuki

    2011-06-17

    Highlights: {yields} The establishment of the ectomesenchymal lineage within the cranial neural crest is of great significance. {yields} Fgf20b knockdown zebrafish embryos showed dysplasticneurocranial and pharyngeal cartilages. {yields} Fgf20b is required for ectomesenchymal fate establishment via the activation of Fgfr1 in zebrafish. -- Abstract: In cranial skeletal development, the establishment of the ectomesenchymal lineage within the cranial neural crest is of great significance. Fgfs are polypeptide growth factors with diverse functions in development and metabolism. Fgf20b knockdown zebrafish embryos showed dysplastic neurocranial and pharyngeal cartilages. Ectomesenchymal cells from cranial neural crest cells were significantly decreased in Fgf20b knockdown embryos, but cranial neural crest cells with a non-ectomesnchymal fate were increased. However, the proliferation and apoptosis of cranial neural crest cells were essentially unchanged. Fgfr1 knockdown embryos also showed dysplastic neurocranial and pharyngeal cartilages. The present findings indicate that Fgf20b is required for ectomesenchymal fate establishment via the activation of Fgfr1 in zebrafish.

  6. Highly transparent and flexible bio-based polyimide/TiO2 and ZrO2 hybrid films with tunable refractive index, Abbe number, and memory properties

    NASA Astrophysics Data System (ADS)

    Huang, Tzu-Tien; Tsai, Chia-Liang; Tateyama, Seiji; Kaneko, Tatsuo; Liou, Guey-Sheng

    2016-06-01

    The novel bio-based polyimide (4ATA-PI) and the corresponding PI hybrids of TiO2 or ZrO2 with excellent optical properties and thermal stability have been prepared successfully. The highly transparent 4ATA-PI containing carboxylic acid groups in the backbone could provide reaction sites for organic-inorganic bonding to obtain homogeneous hybrid films. These PI hybrid films showed a tunable refractive index (1.60-1.81 for 4ATA-PI/TiO2 and 1.60-1.80 for 4ATA-PI/ZrO2), and the 4ATA-PI/ZrO2 hybrid films revealed a higher optical transparency and Abbe's number than those of the 4ATA-PI/TiO2 system due to a larger band gap of ZrO2. By introducing TiO2 and ZrO2 as the electron acceptor into the 4ATA-PI system, the hybrid materials have a lower LUMO energy level which could facilitate and stabilize the charge transfer complex. Therefore, memory devices derived from these PI hybrid films exhibited tunable memory properties from DRAM, SRAM, to WORM with a different TiO2 or ZrO2 content from 0 wt% to 50 wt% with a high ON/OFF ratio (108). In addition, the different energy levels of TiO2 and ZrO2 revealed specifically unique memory characteristics, implying the potential application of the prepared 4ATA-PI/TiO2 and 4ATA-PI/ZrO2 hybrid films in highly transparent memory devices.The novel bio-based polyimide (4ATA-PI) and the corresponding PI hybrids of TiO2 or ZrO2 with excellent optical properties and thermal stability have been prepared successfully. The highly transparent 4ATA-PI containing carboxylic acid groups in the backbone could provide reaction sites for organic-inorganic bonding to obtain homogeneous hybrid films. These PI hybrid films showed a tunable refractive index (1.60-1.81 for 4ATA-PI/TiO2 and 1.60-1.80 for 4ATA-PI/ZrO2), and the 4ATA-PI/ZrO2 hybrid films revealed a higher optical transparency and Abbe's number than those of the 4ATA-PI/TiO2 system due to a larger band gap of ZrO2. By introducing TiO2 and ZrO2 as the electron acceptor into the 4ATA-PI system

  7. Highly transparent and flexible bio-based polyimide/TiO2 and ZrO2 hybrid films with tunable refractive index, Abbe number, and memory properties.

    PubMed

    Huang, Tzu-Tien; Tsai, Chia-Liang; Tateyama, Seiji; Kaneko, Tatsuo; Liou, Guey-Sheng

    2016-07-01

    The novel bio-based polyimide (4ATA-PI) and the corresponding PI hybrids of TiO2 or ZrO2 with excellent optical properties and thermal stability have been prepared successfully. The highly transparent 4ATA-PI containing carboxylic acid groups in the backbone could provide reaction sites for organic-inorganic bonding to obtain homogeneous hybrid films. These PI hybrid films showed a tunable refractive index (1.60-1.81 for 4ATA-PI/TiO2 and 1.60-1.80 for 4ATA-PI/ZrO2), and the 4ATA-PI/ZrO2 hybrid films revealed a higher optical transparency and Abbe's number than those of the 4ATA-PI/TiO2 system due to a larger band gap of ZrO2. By introducing TiO2 and ZrO2 as the electron acceptor into the 4ATA-PI system, the hybrid materials have a lower LUMO energy level which could facilitate and stabilize the charge transfer complex. Therefore, memory devices derived from these PI hybrid films exhibited tunable memory properties from DRAM, SRAM, to WORM with a different TiO2 or ZrO2 content from 0 wt% to 50 wt% with a high ON/OFF ratio (10(8)). In addition, the different energy levels of TiO2 and ZrO2 revealed specifically unique memory characteristics, implying the potential application of the prepared 4ATA-PI/TiO2 and 4ATA-PI/ZrO2 hybrid films in highly transparent memory devices. PMID:27297905

  8. Connecting Teratogen-Induced Congenital Heart Defects to Neural Crest Cells and Their Effect on Cardiac Function

    PubMed Central

    Karunamuni, Ganga H.; Ma, Pei; Gu, Shi; Rollins, Andrew M.; Jenkins, Michael W.; Watanabe, Michiko

    2014-01-01

    Neural crest cells play many key roles in embryonic development, as demonstrated by the abnormalities that result from their specific absence or dysfunction. Unfortunately, these key cells are particularly sensitive to abnormalities in various intrinsic and extrinsic factors, such as genetic deletions or ethanol-exposure that lead to morbidity and mortality for organisms. This review discusses the role identified for a segment of neural crest is in regulating the morphogenesis of the heart and associated great vessels. The paradox is that their derivatives constitute a small proportion of cells to the cardiovascular system. Findings supporting that these cells impact early cardiac function raises the interesting possibility that they indirectly control cardiovascular development at least partially through regulating function. Making connections between insults to the neural crest, cardiac function, and morphogenesis is more approachable with technological advances. Expanding our understanding of early functional consequences could be useful in improving diagnosis and testing therapies. PMID:25220155

  9. Genomic organization of the crested ibis MHC provides new insight into ancestral avian MHC structure

    PubMed Central

    Chen, Li-Cheng; Lan, Hong; Sun, Li; Deng, Yan-Li; Tang, Ke-Yi; Wan, Qiu-Hong

    2015-01-01

    The major histocompatibility complex (MHC) plays an important role in immune response. Avian MHCs are not well characterized, only reporting highly compact Galliformes MHCs and extensively fragmented zebra finch MHC. We report the first genomic structure of an endangered Pelecaniformes (crested ibis) MHC containing 54 genes in three regions spanning ~500 kb. In contrast to the loose BG (26 loci within 265 kb) and Class I (11 within 150) genomic structures, the Core Region is condensed (17 within 85). Furthermore, this Region exhibits a COL11A2 gene, followed by four tandem MHC class II αβ dyads retaining two suites of anciently duplicated “αβ” lineages. Thus, the crested ibis MHC structure is entirely different from the known avian MHC architectures but similar to that of mammalian MHCs, suggesting that the fundamental structure of ancestral avian class II MHCs should be “COL11A2-IIαβ1-IIαβ2.” The gene structures, residue characteristics, and expression levels of the five class I genes reveal inter-locus functional divergence. However, phylogenetic analysis indicates that these five genes generate a well-supported intra-species clade, showing evidence for recent duplications. Our analyses suggest dramatic structural variation among avian MHC lineages, help elucidate avian MHC evolution, and provide a foundation for future conservation studies. PMID:25608659

  10. A multimarker phylogeography of crested newts (Triturus cristatus superspecies) reveals cryptic species.

    PubMed

    Wielstra, B; Baird, A B; Arntzen, J W

    2013-04-01

    The crested newt Triturus cristatus superspecies is composed of five recognized species. One of these, T. karelinii sensu lato, comprises three geographically structured mitochondrial DNA lineages: 'eastern', 'central' and 'western T. karelinii'. Genetic divergence among these lineages is comparable to that of recognized crested newt species, but morphologically they are indistinguishable. Here, we conduct a multimarker phylogeographical survey to explore the evolutionary independence of these mitochondrial DNA lineages and we include representatives of the other species to guide our interpretation of the results. All markers show distinct patterns when analyzed singly (as a phylogeny or haplotype network) and none of them sort haplotypes fully in line with species or mitochondrial DNA lineage. A multilocus approach (BAPS and *BEAST) on the other hand shows that not only the recognized species, but also the three mitochondrial DNA lineages represent discrete nuclear DNA gene pools. A mismatch is found in the northwest of Asiatic Turkey, where several populations identified as 'central T. karelinii' based on nuclear DNA possesses 'western T. karelinii' mitochondrial DNA. We invoke asymmetric mitochondrial DNA introgression to explain this pattern and support this with a historical biogeographical scenario. The three spatial groups in T. karelinii sensu lato should be regarded as distinct species. PMID:23353071

  11. Tail-like anther crest aids pollination by manipulating pollinator's behaviour in a wild ginger.

    PubMed

    Fan, Yong-Li; Li, Qing-Jun

    2016-01-01

    Innovative floral organs are widely distributed taxonomically in angiosperms, and some of them are conspicuous and curious in morphology. Floral organs have long been supposed to play a crucial role in fertilization by pollinators. However, why innovative organs occur, how they are adapted for pollinators and what sexual roles they play are still puzzling. Here we focused on a wild ginger (Zingiber densissimum, Zingiberaceae) and tested the function of the curious anther crest, an innovative floral structure widely distributed in Zingiberaceae. The anther crest is a specialized anther appendage that extends up from the top of the anther to form a tail-like structure, about 150% as long as the anther. We found this structure promoted both the male and the female functions of plants by manipulating its pollinators and causing pollinators to adopt a position ideal for pollen removal and receipt. This study provides a novel example of structure adaptation in which both the male and the female functions are enhanced by resource allocation on a male organ, expanding the knowledge of the sexual roles of the anther appendage. PMID:26928902

  12. Ascaris spp. and Capillaria caudinflata infections in captive-bred crested ibis (Nipponia nippon) in China.

    PubMed

    Zhang, Xu; Qiao, Ji Ying; Wu, Xiao Min; Ma, Qing Yi; Hu, Han; Wang, Jing; Che, Li Feng

    2015-01-01

    Crested ibis (Nipponia nippon), an endan gered native bird, was called the "precious stone" of oriental birds. N. nippon was considered a critically endangered species in the IUCN Red List of Threatened Species and a first-class national protected animal in China. The Chinese government had exerted considerable effort to protect the N. nippon population. An effective approach to increase the number of these birds was captive breeding. However, several pathogens, including parasites, could jeopardize the health of this species. The present study used the fecal flotation method to determine prevalence of intestinal parasites in fresh stool samples by wet mount smearing and iodine staining. Samples were obtained from 63 randomly selected crested ibis bred in Shaanxi Rare Wildlife Rescuing and Breeding Research Center in Zhouzhi County, Xi'an City, Shaanxi Province, China. In the 63 captive individuals, 38 were found positive for intestinal parasites (60.3%, 38/63). Of positive birds, high prevalence of Ascaris spp. (84.2%, 32/38) and Capillaria caudinflata (50.0%, 19/38) were detected. Coccidea (7.8%, 3/38), Fasciolidae (23.7%, 9/38), Blastocystis spp. (15.8%, 6/38), and Entamoeba histolytica (7.8%, 3/38) showed relatively low prevalence rates. This study focuses on the morphological identification of Ascaris spp. and C. caudinflata and their transmission in the N. nippon population. We introduce strategies to improve the breeding management of the birds, enhance their health, and stimulate population productivity. PMID:25486916

  13. ADAM10 is essential for cranial neural crest-derived maxillofacial bone development.

    PubMed

    Tan, Yu; Fu, Runqing; Liu, Jiaqiang; Wu, Yong; Wang, Bo; Jiang, Ning; Nie, Ping; Cao, Haifeng; Yang, Zhi; Fang, Bing

    2016-07-01

    Growth disorders of the craniofacial bones may lead to craniofacial deformities. The majority of maxillofacial bones are derived from cranial neural crest cells via intramembranous bone formation. Any interruption of the craniofacial skeleton development process might lead to craniofacial malformation. A disintegrin and metalloprotease (ADAM)10 plays an essential role in organ development and tissue integrity in different organs. However, little is known about its function in craniofacial bone formation. Therefore, we investigated the role of ADAM10 in the developing craniofacial skeleton, particularly during typical mandibular bone development. First, we showed that ADAM10 was expressed in a specific area of the craniofacial bone and that the expression pattern dynamically changed during normal mouse craniofacial development. Then, we crossed wnt1-cre transgenic mice with adam10-flox mice to generate ADAM10 conditional knockout mice. The stereomicroscopic, radiographic, and von Kossa staining results showed that conditional knockout of ADAM10 in cranial neural crest cells led to embryonic death, craniofacial dysmorphia and bone defects. Furthermore, we demonstrated that impaired mineralization could be triggered by decreased osteoblast differentiation, increased cell death. Overall, these findings show that ADAM10 plays an essential role in craniofacial bone development. PMID:27221046

  14. Imidacloprid Exposure Suppresses Neural Crest Cells Generation during Early Chick Embryo Development.

    PubMed

    Wang, Chao-Jie; Wang, Guang; Wang, Xiao-Yu; Liu, Meng; Chuai, Manli; Lee, Kenneth Ka Ho; He, Xiao-Song; Lu, Da-Xiang; Yang, Xuesong

    2016-06-15

    Imidacloprid is a neonicotinoid pesticide that is widely used in the control pests found on crops and fleas on pets. However, it is still unclear whether imidacloprid exposure could affect early embryo development-despite some studies having been conducted on the gametes. In this study, we demonstrated that imidacloprid exposure could lead to abnormal craniofacial osteogenesis in the developing chick embryo. Cranial neural crest cells (NCCs) are the progenitor cells of the chick cranial skull. We found that the imidacloprid exposure retards the development of gastrulating chick embryos. HNK-1, PAX7, and Ap-2α immunohistological stainings indicated that cranial NCCs generation was inhibited after imidacloprid exposure. Double immunofluorescent staining (Ap-2α and PHIS3 or PAX7 and c-Caspase3) revealed that imidacloprid exposure inhibited both NCC proliferation and apoptosis. In addition, it inhibited NCCs production by repressing Msx1 and BMP4 expression in the developing neural tube and by altering expression of EMT-related adhesion molecules (Cad6B, E-Cadherin, and N-cadherin) in the developing neural crests. We also determined that imidacloprid exposure suppressed cranial NCCs migration and their ability to differentiate. In sum, we have provided experimental evidence that imidacloprid exposure during embryogenesis disrupts NCCs development, which in turn causes defective cranial bone development. PMID:27195532

  15. Ajuba LIM proteins are Snail/Slug corepressors required for neural crest development in Xenopus

    PubMed Central

    Langer, Ellen M.; Feng, Yunfeng; Zhaoyuan, Hou; Rauscher, Frank J.; Kroll, Kristen L.; Longmore, Gregory D.

    2008-01-01

    Snail family transcriptional repressors regulate epithelial mesenchymal transitions during physiological and pathological processes. A conserved SNAG repression domain present in all vertebrate Snail proteins is necessary for repressor complex assembly. Here, we identify the Ajuba family of LIM proteins as functional corepressors of the Snail family via an interaction with the SNAG domain. Ajuba LIM proteins interact with Snail in the nucleus on endogenous E-cadherin promoters and contribute to Snail-dependent repression of E-cadherin. Using Xenopus neural crest as a model of in vivo Snail- or Slug-induced EMT, we demonstrate that Ajuba LIM proteins contribute to neural crest development as Snail/Slug corepressors and are required for in vivo Snail/Slug function. Because Ajuba LIM proteins are also components of adherens junction and contribute to their assembly or stability, their functional interaction with Snail proteins in the nucleus suggests that Ajuba LIM proteins are important regulators of epithelia dynamics communicating surface events with nuclear responses. PMID:18331720

  16. Dynamics of the double-crested cormorant population on Lake Ontario

    USGS Publications Warehouse

    Blackwell, Bradley F.; Stapanian, Martin A.; Weseloh, D.V. Chip

    2002-01-01

    After nearly 30 years of recolonization and expansion across North America, the double-crested cormorant (Phalacrocorax auritus) occupies the role of a perceived and, in some situations, realized threat to fish stocks and other resources. However, population data necessary to plan, defend, and implement management of this species are few. Our purpose was to gain insight into the relative contribution of various population parameters to the overall rate of population growth and identify data needs critical to improving our understanding of the dynamics of double-crested cormorant populations. We demonstrated the construction of a biologically reasonable representation of cormorant population growth on Lake Ontario (1979-2000) by referencing literature values for fertility, age at first breeding, and survival. These parameters were incorporated into a deterministic stage-classified matrix model. By calculating the elasticity of matrix elements (i.e., statgspecific fertility and survival), we found that cormorant population growth on Lake Ontario was most sensitive to survival of birds about to turn age 3 and older. Finally, we demonstrated how this information could be used to evaluate management scenarios and direct future research by simulating potential environmental effects on fertility and survival, as well as a 5-year egg-oiling program. We also demonstrated that survival of older birds exerts more effective population control than changes in fertility.

  17. Ectoparasite load in the crested porcupine Hystrix cristata Linnaeus, 1758 in Central Italy.

    PubMed

    Mori, Emiliano; Sforzi, Andrea; Menchetti, Mattia; Mazza, Giuseppe; Lovari, Sandro; Pisanu, Benoît

    2015-06-01

    The crested porcupine Hystrix cristata is a large body-sized rodent, occurring in Europe only in the Italian Peninsula, where it may have been introduced in early Medieval times. Its parasite fauna is currently poorly known and limited to few anecdotal observations. We have analyzed the ectoparasite load of 165 crested porcupines from Tuscany and Latium (Central Italy). Both captured and road-killed individuals were checked for fleas and ticks. Overall, only 39 porcupines were infested by four species of ticks and five of fleas. Abundance of ectoparasites was higher in areas with higher habitat richness, with respect to densely wooded areas. The most frequent species was the flea Pulex irritans (25%), whose prevalence peaked in winter probably because of optimal abiotic conditions in the porcupine's den. The remaining species of both hard ticks (Rhipicephalus bursa, Pholeoixodes hexagonus, and Ixodes ventalloi) and fleas (Paraceras melis, Ctenocephalides canis, Dasypsyllus gallinulae, and Hystrichopsylla talpae), all with prevalence lower than 5%, could be due to den sharing with other vertebrates, mainly carnivores such as, e.g., red foxes and badgers. The second most prevalent species was the generalist tick Ixodes ricinus (21%). An adult male-biased parasitism for ticks has been detected, suggesting a possible role of testosterone related immune-depressive effect. The low richness in dominant ectoparasite species, built up by locally acquired generalist taxa, provides support to the allochthonous origin of this rodent in Italy. PMID:25773184

  18. Field evaluation of some bait additives against Indian crested porcupine (Hystrix indica) (Rodentia: Hystricidae).

    PubMed

    Mushtaq, Muhammad; Hussain, Iftikhar; Mian, Afsar; Munir, Shahid; Ahmed, Irfan; Khan, Abdul Aziz

    2013-09-01

    This research study evaluated the effect of different additives on the bait consumption by Indian crested porcupine, a serious forest and agricultural pest, under field conditions. Different additives (saccharin, common salt, bone meal, fish meal, peanut butter, egg yolk, egg shell powder, yeast powder, mineral oil and coconut oil) at 2 and 5% each were tested for their relative preference, using groundnut-maize (1:1) as basic bait. All the additives were tested under a no-choice test pattern. For control tests, no additive was mixed with the basic bait. Saccharin at 5% concentration significantly enhanced the consumption of bait over the basic bait, while 2% saccharin supplemented bait resulted in a non-significant bait consumption. All other additives did not enhance the consumption of the bait material; rather, these worked as repellents. However, the repellency was lowest with the common salt, followed by egg yolk, egg shell powder, bone meal, peanut butter, mineral oil, fish meal and yeast powder, while coconut remained the most repellent compound. The present study suggested that groundnut-maize (1:1) supplemented with 5% saccharin was the preferred bait combination, and can be used with different rodenticides for the management of Indian crested porcupine. PMID:24020467

  19. In vivo impact of Dlx3 conditional inactivation in Neural Crest-Derived Craniofacial Bones

    PubMed Central

    Duverger, Olivier; Isaac, Juliane; Zah, Angela; Hwang, Joonsung; Berdal, Ariane; Lian, Jane B.; Morasso, Maria I.

    2012-01-01

    Mutations in DLX3 in humans lead to defects in craniofacial and appendicular bones, yet the in vivo activity related to Dlx3 function during normal skeletal development have not been fully elucidated. Here we used a conditional knockout approach to analyze the effects of neural crest deletion of Dlx3 on craniofacial bones development. At birth, mutant mice exhibit a normal overall positioning of the skull bones, but a change in the shape of the calvaria was observed. Molecular analysis of the genes affected in the frontal bones and mandibles from these mice identified several bone markers known to affect bone development, with a strong prediction for increased bone formation and mineralization in vivo. Interestingly, while a subset of these genes were similarly affected in frontal bones and mandibles (Sost, Mepe, Bglap, Alp, Ibsp, Agt), several genes, including Lect1 and Calca, were specifically affected in frontal bones. Consistent with these molecular alterations, cells isolated from the frontal bone of mutant mice exhibited increased differentiation and mineralization capacities ex vivo, supporting cell autonomous defects in neural crest cells. However, adult mutant animals exhibited decreased bone mineral density in both mandibles and calvaria, as well as a significant increase in bone porosity. Together, these observations suggest that mature osteoblasts in the adult respond to signals that regulate adult bone mass and remodeling. This study provides new downstream targets for Dlx3 in craniofacial bone, and gives additional evidence of the complex regulation of bone formation and homeostasis in the adult skeleton. PMID:22886599

  20. Misexpression of Pknox2 in mouse limb bud mesenchyme perturbs zeugopod development and deltoid crest formation.

    PubMed

    Zhou, Wenrong; Zhu, Huang; Zhao, Jianzhi; Li, Hanjun; Wan, Yong; Cao, Jingjing; Zhao, Haixia; Yu, Jian; Zhou, Rujiang; Yao, Yiyun; Zhang, Lingling; Wang, Lifang; He, Lin; Ma, Gang; Yao, Zhengju; Guo, Xizhi

    2013-01-01

    The TALE (Three Amino acid Loop Extension) family consisting of Meis, Pbx and Pknox proteins is a group of transcriptional co-factors with atypical homeodomains that play pivotal roles in limb development. Compared to the in-depth investigations of Meis and Pbx protein functions, the role of Pknox2 in limb development remains unclear. Here, we showed that Pknox2 was mainly expressed in the zeugopod domain of the murine limb at E10.5 and E11.5. Misexpression of Pknox2 in the limb bud mesenchyme of transgenic mice led to deformities in the zeugopod and forelimb stylopod deltoid crest, but left the autopod and other stylopod skeletons largely intact. These malformations in zeugopod skeletons were recapitulated in mice overexpressing Pknox2 in osteochondroprogenitor cells. Molecular and cellular analyses indicated that the misexpression of Pknox2 in limb bud mesenchyme perturbed the Hox10-11 gene expression profiles, decreased Col2 expression and Bmp/Smad signaling activity in the limb. These results indicated that Pknox2 misexpression affected mesenchymal condensation and early chondrogenic differentiation in the zeugopod skeletons of transgenic embryos, suggesting Pknox2 as a potential regulator of zeugopod and deltoid crest formation. PMID:23717575

  1. The Tallahala Creek Complex, Smith County, Mississippi: The crest is not always the best

    SciTech Connect

    Sticker, E.E.

    1994-09-01

    The Tallahala Creek complex, comprising both Tallahala Creek and East Tallahala Creek fields, is a salt-induced anticline transacted by two down-to-the-north fault systems. Since 1967, the upper portion of the Jurassic Smackover Formation has yielded almost 15 million bbl of oil and 20 billion ft{sup 3} of gas, or 75% and 64% of the total oil and gas, respectively, produced from the fields. Contemporaneous sediment accumulation and structural growth have created various lithofacies in the upper Smackover, thereby significantly affecting reservoir heterogeneity. These lithofacies can be delineated by their structural position on the anticline. On the most downdip and downthrown portions of the structure, the Lipper Smackover consists of a series of gray, fine to medium-grained sandstones separated by limestones. These sandstones generally exhibit both high porosity and permeability, and have thus contributed over 95% of the total Smackover production. Updip the upper Smackover becomes increasingly calcareous, finally grading into a sandy, occasionally dolomitic, limestone on the crest and southern upthrown flank of the anticline. This limestone lithofacies has been noncommercial as a reservoir rock, as evidenced by the less than 7000 bbl of oil cumulatively produced from the Smackover in two of the structurally highest wells, the Shell 2 E. M. Lane and the Shell 1 F. James. Structural and stratigraphic relationships discovered through field development of the Tallahala Creek complex have significantly altered the conventional idea that {open_quotes}the crest is always the best.{close_quotes}

  2. High glucose environment inhibits cranial neural crest survival by activating excessive autophagy in the chick embryo

    PubMed Central

    Wang, Xiao-Yu; Li, Shuai; Wang, Guang; Ma, Zheng-Lai; Chuai, Manli; Cao, Liu; Yang, Xuesong

    2015-01-01

    High glucose levels induced by maternal diabetes could lead to defects in neural crest development during embryogenesis, but the cellular mechanism is still not understood. In this study, we observed a defect in chick cranial skeleton, especially parietal bone development in the presence of high glucose levels, which is derived from cranial neural crest cells (CNCC). In early chick embryo, we found that inducing high glucose levels could inhibit the development of CNCC, however, cell proliferation was not significantly involved. Nevertheless, apoptotic CNCC increased in the presence of high levels of glucose. In addition, the expression of apoptosis and autophagy relevant genes were elevated by high glucose treatment. Next, the application of beads soaked in either an autophagy stimulator (Tunicamycin) or inhibitor (Hydroxychloroquine) functionally proved that autophagy was involved in regulating the production of CNCC in the presence of high glucose levels. Our observations suggest that the ERK pathway, rather than the mTOR pathway, most likely participates in mediating the autophagy induced by high glucose. Taken together, our observations indicated that exposure to high levels of glucose could inhibit the survival of CNCC by affecting cell apoptosis, which might result from the dysregulation of the autophagic process. PMID:26671447

  3. Diet of the double-crested cormorant in western Lake Erie

    USGS Publications Warehouse

    Bur, Michael T.; Tinnirello, Sandra L.; Lovell, Charles D.; Tyson, Jeff T.

    1999-01-01

    Sport and commercial fishing interest groups are concerned about potential impacts double-crested cormorants (Phalacrocorax auritus) may have on fish species. Our objectives for this study were to determine the diet of the cormorant in western Lake Erie and the diet overlap and competition for resources with piscivorous fish, such as walleye (Stizostedion vitreum). The stomach contents of 302 double-crested cormorants collected in western Lake Erie consisted primarily of young-of-the-year gizzard shad (Dorosoma cepedianum), emerald shiner (Notropis atherinoides), and freshwater drum (Aplodinotus grunniens). In the spring, freshwater drum were the most frequently occurring food in the stomachs and constituted the greatest portion of the diet by weight. Young gizzard shad became the most abundant prey and made up the largest percentage of the diet by weight in the stomachs from the end of July through October. Emerald shiners were abundant in the diet during June, September, and October. The fish species that cormorants ate resembled, by proportion, the species mix found in trawl catches. The diets of cormorants and walleyes were similar from July to October with significant overlap. Results from this study suggest impacts of cormorants at current population levels in Lake Erie are not detrimental to sport and commercial fishing. Therefore, control for the purpose of reducing competition for prey fish with walleye is not warranted at this time.

  4. Organochlorine contaminants and reproductive success of double-crested cormorants from Green Bay, Wisconsin, USA

    USGS Publications Warehouse

    Custer, T.W.; Custer, Christine M.; Hines, R.K.; Gutreuter, S.; Stromborg, K.L.; Allen, P.D.; Melancon, M.J.

    1999-01-01

    In 1994 and 1995, nesting success of double-crested cormorants (Phalacrocorax auritus) was measured at Cat Island, in southern Green Bay, Lake Michigan, Wisconsin, USA. Sample eggs at pipping and unhatched eggs were collected and analyzed for organochlorines (including total polychlorinated biphenyls [PCBs] and DDE), hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity in embryos, and eggshell thickness. Of 1,570 eggs laid, 32% did not hatch and 0.4% had deformed embryos. Of 632 chicks monitored from hatching to 12 d of age, 9% were missing or found dead; no deformities were observed. The PCB concentrations in sample eggs from clutches with deformed embryos (mean = 10.2 I?g/g wet weight) and dead embryos (11.4 I?g/g) were not significantly higher than concentrations in sample eggs from nests where all eggs hatched (12.1 I?g/g). A logistic regression of hatching success versus DDE, dieldrin, and PCB concentrations in sibling eggs identified DDE and not dieldrin or PCBs as a significant risk factor. A logistic regression of hatching success versus DDE and eggshell thickness implicated DDE and not eggshell thickness as a significant risk factor. Even though the insecticide DDT was banned in the early 1970s, we suggest that DDE concentrations in double-crested cormorant eggs in Green Bay are still having an effect on reproduction in this species.

  5. Organochlorine contaminants and reproductive success of Double-crested Cormorants from Green Bay, Wisconsin, USA

    USGS Publications Warehouse

    Custer, T.W.; Custer, Christine M.; Hines, R.K.; Gutreuter, S.; Stromborg, K.L.; Allen, P.D.; Melancon, M.J.

    1999-01-01

    In 1994 and 1995, nesting success of double-crested cormorants (Phalacrocorax auritus) was measured at Cat Island, in southern Green Bay, Lake Michigan, Wisconsin, USA. Sample eggs at pipping and unhatched eggs were collected and analyzed for organochlorines (including total polychlorinated biphenyls [PCBs] and DDE), hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity in embryos, and eggshell thickness. Of 1,570 eggs laid, 32% did not hatch and 0.4% had deformed embryos. Of 632 chicks monitored from hatching to 12 d of age, 9% were missing or found dead; no deformities were observed. The PCB concentrations in sample eggs from clutches with deformed embryos (mean = 10.2 ?g/g wet weight) and dead embryos (11.4 ?g/g) were not significantly higher than concentrations in sample eggs from nests where all eggs hatched (12.1 ?g/g). A logistic regression of hatching success versus DDE, dieldrin, and PCB concentrations in sibling eggs identified DDE and not dieldrin or PCBs as a significant risk factor. A logistic regression of hatching success versus DDE and eggshell thickness implicated DDE and not eggshell thickness as a significant risk factor. Even though the insecticide DDT was banned in the early 1970s, we suggest that DDE concentrations in double-crested cormorant eggs in Green Bay are still having an effect on reproduction in this species.

  6. Frontal Sinus Obliteration with Iliac Crest Bone Grafts. Review of 8 Cases

    PubMed Central

    Monnazzi, Marcelo; Gabrielli, Marisa; Pereira-Filho, Valfrido; Hochuli-Vieira, Eduardo; de Oliveira, Henrique; Gabrielli, Mario

    2014-01-01

    This study evaluated postoperative results of 8 cases of frontal sinus fractures treated by frontal sinus obliteration with autogenous bone from the anterior iliac crest. Patients and methods: The medical charts of patients sequentially treated for frontal sinus fractures by obliteration with autogenous cancellous iliac crest bone in the Oral and Maxillofacial Surgery Division of this institution were reviewed. From those, eight had complete records and adequately described long-term follow-up. All were operated by the same surgical team. Those patients were recalled and independently evaluated by 2 examiners. Radiographs and/or CT scans were available for this evaluation. Associated fractures and complications were noted. The average postoperative follow-up was 7 years, ranging from 3 to 16 years. The main complication was infection. Four patients (50%) had uneventful long-term follow-ups and four (50%) experienced complications requiring reoperation. Based on the studied sample studied the authors conclude that the obliteration with autogenous bone presented a high percentage of complications in this series. PMID:25383146

  7. Modelling shock to detonation transition in PETN using HERMES and CREST

    NASA Astrophysics Data System (ADS)

    Maheswaran, Mary-Ann; Curtis, John; Reaugh, Jack

    2013-06-01

    The High Explosive Response to MEchanical Stimulus (HERMES) model has been developed to address High Explosive Violent Response (HEVR). It is a material model for use in the both the LS-DYNA finite element and ALE3D hydrocodes that enables the modelling of both shock to detonation (SDT) and deflagration to detonation (DDT) transition. As part of its ongoing development and application, model parameters for the explosive PETN were found by using experimental data for PETN at different densities. PETN was selected because of the availability of both SDT and DDT data. To model SDT and DDT, HERMES uses a subset of the CREST reactive burn model with the Mie-Gruneisen equation of state (EOS) for the unreacted explosive and a look-up table for the gas EOS as generated by Cheetah. The unreacted EOS parameters were found first by calculating the principal isentrope of unreacted PETN at TMD from PETN shock Hugoniot data. Then Pop-plot data for PETN was used to fit the CREST parameters at each density. The resulting new PETN HERMES material model provides a platform for further investigations of SDT and DDT in low density PETN powder. JER's activity was performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344, and partially funded by the Joint US DoD/DOE Munitions Technology Development Program.

  8. A role for chemokine signaling in neural crest cell migration and craniofacial development

    PubMed Central

    Killian, Eugenia C. Olesnicky; Birkholz, Denise A.; Artinger, Kristin Bruk

    2009-01-01

    Neural crest cells (NCCs) are a unique population of multipotent cells that migrate along defined pathways throughout the embryo and give rise to many diverse cell types including pigment cells, craniofacial cartilage and the peripheral nervous system (PNS). Aberrant migration of NCCs results in a wide variety of congenital birth defects including craniofacial abnormalities. The chemokine Sdf1 and its receptors, Cxcr4 and Cxcr7, have been identified as key components in the regulation of cell migration in a variety of tissues. Here we describe a novel role for the zebrafish chemokine receptor Cxcr4a in the development and migration of cranial NCCs (CNCCs). We find that loss of Cxcr4a, but not Cxcr7b results in aberrant CNCC migration, defects in the neurocranium, as well as cranial ganglia dismorphogenesis. Moreover, overexpression of either Sdf1b or Cxcr4a causes aberrant CNCC migration and results in ectopic craniofacial cartilages. We propose a model in which Sdf1b signaling from the pharyngeal arch endoderm and optic stalk to Cxcr4a expressing CNCCs is important for both the proper condensation of the CNCCs into pharyngeal arches and the subsequent patterning and morphogenesis of the neural crest derived tissues. PMID:19576198

  9. Parentage and relatedness in polyandrous comb-crested jacanas using ISSRs

    USGS Publications Warehouse

    Haig, Susan M.; Mace, Terrence R.; Mullins, Thomas D.

    2003-01-01

    In this article we present the first analysis of parentage and relatedness in a natural vertebrate population, using Intersimple Sequence Repeat (ISSR) markers. Thus, 28 ISSR markers were used in a study of a sex-role reversed, simultaneously polyandrous shorebird from northeastern Australia, the comb-crested jacana (Irediparra gallinacea). Assessment of parentage was based on comparison of field observations, novel bands, individual-specific bands found in 7/9 males and 4/6 females, and a 99% CI exclusion criteria. Integrating results from these approaches resulted in confirmation of paternity in all 36 chicks. In only one case (2.8% of chicks) was a co-mate assigned paternity. Thus, comb-crested jacanas appear to be genetically monogamous. These results showed resemblance to sequentially polyandrous birds but differed from the simultaneously polyandrous wattled jacana ( Jacana jacana; Emlen et al. 1998). A significant relationship between relatedness and ISSR similarity resulted in recognition that 14/15 adults sampled may be related to at least one other adult by 0.25 or more. Lack of dispersal may be explained by physical limitations and adequate regional habitat. ISSRs proved to be simple and helpful in resolving these issues.

  10. Zebrafish heart development is regulated via glutaredoxin 2 dependent migration and survival of neural crest cells

    PubMed Central

    Berndt, Carsten; Poschmann, Gereon; Stühler, Kai; Holmgren, Arne; Bräutigam, Lars

    2014-01-01

    Glutaredoxin 2 is a vertebrate specific oxidoreductase of the thioredoxin family of proteins modulating the intracellular thiol pool. Thereby, glutaredoxin 2 is important for specific redox signaling and regulates embryonic development of brain and vasculature via reversible oxidative posttranslational thiol modifications. Here, we describe that glutaredoxin 2 is also required for successful heart formation. Knock-down of glutaredoxin 2 in zebrafish embryos inhibits the invasion of cardiac neural crest cells into the primary heart field. This leads to impaired heart looping and subsequent obstructed blood flow. Glutaredoxin 2 specificity of the observed phenotype was confirmed by rescue experiments. Active site variants of glutaredoxin 2 revealed that the (de)-glutathionylation activity is required for proper heart formation. Our data suggest that actin might be one target during glutaredoxin 2 regulated cardiac neural crest cell migration and embryonic heart development. In summary, this work represents further evidence for the general importance of redox signaling in embryonic development and highlights additionally the importance of glutaredoxin 2 during embryogenesis. PMID:24944912

  11. Combination of microvascular medial femoral condyle and iliac crest flap for hemi-midface reconstruction.

    PubMed

    Brandtner, C; Hachleitner, J; Buerger, H; Gaggl, A

    2015-06-01

    In midface defects including the orbit (Brown class III and IV), no single flap can provide adequate reconstruction. In this technical note, the combination of vascularized iliac crest flap and vascularized medial femoral condyle flap (MFC) is described. The vascularized iliac crest flap is reported to be the gold standard for maxilla reconstruction. There is, however, no consensus on the best method for orbital and nasal wall reconstruction. The MFC flap can be harvested as a thin corticoperiosteal flap or as an osteomyocutaneous flap. Due to the periosteal blood supply, this flap can be customized for an individual defect of the upper hemi-midface. It is therefore of great benefit in orbital and nasal wall reconstruction. By combining the deep circumflex iliac artery (DCIA) bone flap and the MFC flap, the best standard reconstruction technique of the hemi-maxilla can be combined with a new anatomical precise microvascular reconstruction technique of the orbit. A nearly symmetric midface appearance can be achieved. PMID:25835757

  12. 3D laboratory experiments on a system of low-crested breakwaters under oblique wave attack

    NASA Astrophysics Data System (ADS)

    Papacharalampous, Georgia; Karantinos, Michalis; Giantsi, Theodora; Moutzouris, Constantinos

    2016-04-01

    Low-crested breakwaters are being increasingly used for shore protection. Hydrodynamics around coastal structures are complicated and have not been fully understood. A series of large scale (1:40) 3D laboratory experiments were carried out in the Laboratory of Harbour Works, National Technical University of Athens to investigate the wave disturbance around a system of two non-parallel to the shoreline breakwaters. The structures were of the type of low-crested, permeable and attacked by obliquely incident waves. Three different water depths were tested in the basin with a range of various different spectra. The transmission and reflection coefficients were measured in the middle of each breakwater. For this purpose, 1 gauge and 4 gauges (in line) were placed on the landward and seaward side of each breakwater respectively. The effect of diffraction is incorporate at the measured wave heights. The measured coefficients are being compared to their corresponding estimated using existing empirical formulas. Most of those formulas neglect wave obliquity.

  13. Combined function of HoxA and HoxB clusters in neural crest cells.

    PubMed

    Vieux-Rochas, Maxence; Mascrez, Bénédicte; Krumlauf, Robb; Duboule, Denis

    2013-10-01

    The evolution of chordates was accompanied by critical anatomical innovations in craniofacial development, along with the emergence of neural crest cells. The potential of these cells to implement a craniofacial program in part depends upon the (non-)expression of Hox genes. For instance, the development of jaws requires the inhibition of Hox genes function in the first pharyngeal arch. In contrast, Hox gene products induce craniofacial structures in more caudal territories. To further investigate which Hox gene clusters are involved in this latter role, we generated HoxA;HoxB cluster double mutant animals in cranial neural crest cells. We observed the appearance of a supernumerary dentary-like bone with an endochondral ossification around a neo-Meckel's cartilage matrix and an attachment of neo-muscle demonstrating that HoxB genes enhance the phenotype induced by the deletion of the HoxA cluster alone. In addition, a cervical and hypertrophic thymus was associated with the supernumerary dentary-like bone, which may reflect its ancestral position near the filtrating system. Altogether these results show that the HoxA and HoxB clusters cooperated during evolution to lead to present craniofacial diversity. PMID:23850771

  14. A New Crested Pterosaur from the Early Cretaceous of Spain: The First European Tapejarid (Pterodactyloidea: Azhdarchoidea)

    PubMed Central

    Vullo, Romain; Marugán-Lobón, Jesús; Kellner, Alexander W. A.; Buscalioni, Angela D.; Gomez, Bernard; de la Fuente, Montserrat; Moratalla, José J.

    2012-01-01

    Background The Tapejaridae is a group of unusual toothless pterosaurs characterized by bizarre cranial crests. From a paleoecological point of view, frugivorous feeding habits have often been suggested for one of its included clades, the Tapejarinae. So far, the presence of these intriguing flying reptiles has been unambiguously documented from Early Cretaceous sites in China and Brazil, where pterosaur fossils are less rare and fragmentary than in similarly-aged European strata. Methodology/Principal Findings Europejara olcadesorum gen. et sp. nov. is diagnosed by a unique combination of characters including an unusual caudally recurved dentary crest. It represents the oldest known member of Tapejaridae and the oldest known toothless pterosaur. The new taxon documents the earliest stage of the acquisition of this anatomical feature during the evolutionary history of the Pterodactyloidea. This innovation may have been linked to the development of new feeding strategies. Conclusion/Significance The discovery of Europejara in the Barremian of the Iberian Peninsula reveals an earlier and broader global distribution of tapejarids, suggesting a Eurasian origin of this group. It adds to the poorly known pterosaur fauna of the Las Hoyas locality and contributes to a better understanding of the paleoecology of this Konservat-Lagerstätte. Finally, the significance of a probable contribution of tapejarine tapejarids to the early angiosperm dispersal is discussed. PMID:22802931

  15. Can footwall unloading explain late Cenozoic uplift of the Sierra Nevada crest?

    USGS Publications Warehouse

    Thompson, G.A.; Parsons, T.

    2009-01-01

    Globally, normal-fault displacement bends and warps rift flanks upwards, as adjoining basins drop downwards. Perhaps the most evident manifestations are the flanks of the East African Rift, which cuts across the otherwise minimally deformed continent. Flank uplift was explained by Vening Meinesz (1950, Institut Royal Colonial Belge, Bulletin des Seances, v. 21, p. 539-552), who recognized that isostasy should cause uplift of a normal-faulted footwall and subsidence of its hanging wall. Uplift occurs because slip on a dipping normal fault creates a broader root of less-dense material beneath the footwall, and a narrowed one beneath the hanging wall. In this paper, we investigate the potential influence of this process on the latest stages of Sierra Nevada uplift. Through theoretical calculations and 3D finite element modelling, we find that cumulative slip of about 4km on range-front faults would have produced about 1.3km peak isostatic uplift at the ridge crest. Numerical models suggest that the zone of uplift is narrow, with the width controlled by bending resistance of the seismogenic crust. We conclude that footwall unloading cannot account for the entire elevation of the Sierran crest above sea level, but if range-front faulting initiated in an already elevated plateau like the adjacent Basin and Range Province, then a hybrid model of pre-existing regional uplift and localized footwall unloading can account for the older and newer uplift phases suggested by the geologic record.

  16. Ionospheric effects of the solar eclipse of September 23, 1987, around the equatorial anomaly crest region

    SciTech Connect

    Kang Cheng; Yinnnien Huang; Senwen Chen )

    1992-01-01

    The ionospheric responses to the solar eclipse of September 23, 1987, in the equatorial anomaly crest region have been investigated by using ionospheric vertical sounding, VLF propagation delay time, and differential Doppler shift data observed at Chungli, which is located near the northern equatorial anomaly crest region. It has been found that temporal variations of the F{sub 1} layer and D region are mainly controlled by local solar radiation. Quantitative analysis of the variations of the F{sub 1} layer critical frequency, F{sub o} F{sub 1}, shows that electrons are removed from the F{sub 1} layer through ionic recombination. However, the temporal variations of f{sub o}F{sub 2} and electron density above 200 km show that the variations o the F{sub 2} layer around the equatorial anomaly region are controlled not by local solar radiation but by solar radiation at the equator. The fountain effect plays an important role even during the solar eclipse. The VLF propagation time delay is controlled by the variations of average path obscuration. Atmospheric gravity waves produced by the moving bow wave front of the solar eclipse are found with a period around 17-23 min and wavelength about 293 km.

  17. Neurogenesis of neural crest-derived periodontal ligament stem cells by EGF and bFGF.

    PubMed

    Fortino, Veronica R; Chen, Ren-Shiang; Pelaez, Daniel; Cheung, Herman S

    2014-04-01

    Neuroregenerative medicine is an ever-growing field in which regeneration of lost cells/tissues due to a neurodegenerative disease is the ultimate goal. With the scarcity of available replacement alternatives, stem cells provide an attractive source for regenerating neural tissue. While many stem cell sources exist, including: mesenchymal stem cells, embryonic stem cells, and induced pluripotent stem cells, the limited cellular potency, technical difficulties, and ethical considerations associated with these make finding alternate sources a desirable goal. Periodontal ligament stem cells (PDLSCs) derived from the neural crest were induced into neural-like cells using a combination of epidermal growth factor, and basic fibroblast growth factor. Morphological changes were evident in our treated group, seen under both light microscopy and scanning electron microscopy. A statistically significant increase in the expression of neuron-specific β-tubulin III and the neural stem/progenitor cell marker nestin, along with positive immunohistochemical staining for glial fibrillary acidic protein, demonstrated the success of our treatment in inducing both neuronal and glial phenotypes. Positive staining for synaptophysin demonstrated neural connections and electrophysiological recordings indicated that when subjected to whole-cell patch clamping, our treated cells displayed inward currents conducted through voltage-gated sodium (Na(+) ) channels. Taken together, our results indicate the success of our treatment in inducing PDLSCs to neural-like cells. The ease of sourcing and expansion, their embryologic neural crest origin, and the lack of ethical implications in their use make PDLSCs an attractive source for use in neuroregenerative medicine. PMID:24105823

  18. In vivo impact of Dlx3 conditional inactivation in neural crest-derived craniofacial bones.

    PubMed

    Duverger, Olivier; Isaac, Juliane; Zah, Angela; Hwang, Joonsung; Berdal, Ariane; Lian, Jane B; Morasso, Maria I

    2013-03-01

    Mutations in DLX3 in humans lead to defects in craniofacial and appendicular bones, yet the in vivo activities related to Dlx3 function during normal skeletal development have not been fully elucidated. Here we used a conditional knockout approach to analyze the effects of neural crest deletion of Dlx3 on craniofacial bones development. At birth, mutant mice exhibit a normal overall positioning of the skull bones, but a change in the shape of the calvaria was observed. Molecular analysis of the genes affected in the frontal bones and mandibles from these mice identified several bone markers known to affect bone development, with a strong prediction for increased bone formation and mineralization in vivo. Interestingly, while a subset of these genes were similarly affected in frontal bones and mandibles (Sost, Mepe, Bglap, Alp, Ibsp, Agt), several genes, including Lect1 and Calca, were specifically affected in frontal bones. Consistent with these molecular alterations, cells isolated from the frontal bone of mutant mice exhibited increased differentiation and mineralization capacities ex vivo, supporting cell autonomous defects in neural crest cells. However, adult mutant animals exhibited decreased bone mineral density in both mandibles and calvaria, as well as a significant increase in bone porosity. Together, these observations suggest that mature osteoblasts in the adult respond to signals that regulate adult bone mass and remodeling. This study provides new downstream targets for Dlx3 in craniofacial bone, and gives additional evidence of the complex regulation of bone formation and homeostasis in the adult skeleton. PMID:22886599

  19. Isolation of neural crest derived chromaffin progenitors from adult adrenal medulla.

    PubMed

    Chung, Kuei-Fang; Sicard, Flavie; Vukicevic, Vladimir; Hermann, Andreas; Storch, Alexander; Huttner, Wieland B; Bornstein, Stefan R; Ehrhart-Bornstein, Monika

    2009-10-01

    Chromaffin cells of the adrenal medulla are neural crest-derived cells of the sympathoadrenal lineage. Unlike the closely-related sympathetic neurons, a subpopulation of proliferation-competent cells exists even in the adult. Here, we describe the isolation, expansion, and in vitro characterization of proliferation-competent progenitor cells from the bovine adrenal medulla. Similar to neurospheres, these cells, when prevented from adherence to the culture dish, grew in spheres, which we named chromospheres. These chromospheres were devoid of mRNA specific for smooth muscle cells (MYH11) or endothelial cells (PECAM1). During sphere formation, markers for differentiated chromaffin cells, such as phenylethanolamine-N-methyl transferase, were downregulated while neural progenitor markers nestin, vimentin, musashi 1, and nerve growth factor receptor, as well as markers of neural crest progenitor cells such as Sox1 and Sox9, were upregulated. Clonal analysis and bromo-2'-deoxyuridine-incorporation analysis demonstrated the self-renewing capacity of chromosphere cells. Differentiation protocols using NGF and BMP4 or dexamethasone induced neuronal or endocrine differentiation, respectively. Electrophysiological analyses of neural cells derived from chromospheres revealed functional properties of mature nerve cells, such as tetrodotoxin-sensitive sodium channels and action potentials. Our study provides evidence that proliferation and differentiation competent chromaffin progenitor cells can be isolated from adult adrenal medulla and that these cells might harbor the potential for the treatment of neurodegenerative diseases, such as Parkinson's disease. PMID:19609938

  20. A gradient-based approach for automated crest-line detection and analysis of sand dune patterns on planetary surfaces

    NASA Astrophysics Data System (ADS)

    Lancaster, N.; LeBlanc, D.; Bebis, G.; Nicolescu, M.

    2015-12-01

    Dune-field patterns are believed to behave as self-organizing systems, but what causes the patterns to form is still poorly understood. The most obvious (and in many cases the most significant) aspect of a dune system is the pattern of dune crest lines. Extracting meaningful features such as crest length, orientation, spacing, bifurcations, and merging of crests from image data can reveal important information about the specific dune-field morphological properties, development, and response to changes in boundary conditions, but manual methods are labor-intensive and time-consuming. We are developing the capability to recognize and characterize patterns of sand dunes on planetary surfaces. Our goal is to develop a robust methodology and the necessary algorithms for automated or semi-automated extraction of dune morphometric information from image data. Our main approach uses image processing methods to extract gradient information from satellite images of dune fields. Typically, the gradients have a dominant magnitude and orientation. In many cases, the images have two major dominant gradient orientations, for the sunny and shaded side of the dunes. A histogram of the gradient orientations is used to determine the dominant orientation. A threshold is applied to the image based on gradient orientations which agree with the dominant orientation. The contours of the binary image can then be used to determine the dune crest-lines, based on pixel intensity values. Once the crest-lines have been extracted, the morphological properties can be computed. We have tested our approach on a variety of images of linear and crescentic (transverse) dunes and compared dune detection algorithms with manually-digitized dune crest lines, achieving true positive values of 0.57-0.99; and false positives values of 0.30-0.67, indicating that out approach is generally robust.

  1. Gastrointestinal and external parasites of the white-crested elaenia Elaenia albiceps chilensis (Aves, Tyrannidae) in Chile.

    PubMed

    Fuentes, Danny; Reyes, Jaime; Sepúlveda, María Soledad; Kinsella, Mike; Mironov, Sergey; Cicchino, Armando; Moreno, Lucila; Landaeta-Aqueveque, Carlos; Troncoso, Ignacio; González-Acuña, Daniel

    2015-01-01

    The objective of this study is to evaluate the ectoparasites and helminths of the white-crested elaenia, Elaenia albiceps chilensis. Feather mites Anisophyllodes elaeniae, Trouessartia elaeniae, and Analges sp. were detected in 51% of birds (n=106), whereas 24% were infected with lice (Tyranniphilopterus delicatulus, Menacanthus cfr. distinctus, and Ricinus cfr. invadens). Helminths Viguiera sp. and Capillaria sp. were found in five of the birds that were necropsied (n=20). With the exception of A. elaeniae, T. elaeniae, and T. delicatulus, all parasites represented new records found for the white-crested elaenia, and therefore for the Chilean repertoire of biodiversity. PMID:26444059

  2. Gene array analysis of neural crest cells identifies transcription factors necessary for direct conversion of embryonic fibroblasts into neural crest cells

    PubMed Central

    Motohashi, Tsutomu; Watanabe, Natsuki; Nishioka, Masahiro; Nakatake, Yuhki; Yulan, Piao; Mochizuki, Hiromi; Kawamura, Yoshifumi; Ko, Minoru S. H.; Goshima, Naoki; Kunisada, Takahiro

    2016-01-01

    ABSTRACT Neural crest cells (NC cells) are multipotent cells that emerge from the edge of the neural folds and migrate throughout the developing embryo. Although the gene regulatory network for generation of NC cells has been elucidated in detail, it has not been revealed which of the factors in the network are pivotal to directing NC identity. In this study we analyzed the gene expression profile of a pure NC subpopulation isolated from Sox10-IRES-Venus mice and investigated whether these genes played a key role in the direct conversion of Sox10-IRES-Venus mouse embryonic fibroblasts (MEFs) into NC cells. The comparative molecular profiles of NC cells and neural tube cells in 9.5-day embryos revealed genes including transcription factors selectively expressed in developing trunk NC cells. Among 25 NC cell-specific transcription factor genes tested, SOX10 and SOX9 were capable of converting MEFs into SOX10-positive (SOX10+) cells. The SOX10+ cells were then shown to differentiate into neurons, glial cells, smooth muscle cells, adipocytes and osteoblasts. These SOX10+ cells also showed limited self-renewal ability, suggesting that SOX10 and SOX9 directly converted MEFs into NC cells. Conversely, the remaining transcription factors, including well-known NC cell specifiers, were unable to convert MEFs into SOX10+ NC cells. These results suggest that SOX10 and SOX9 are the key factors necessary for the direct conversion of MEFs into NC cells. PMID:26873953

  3. Gene array analysis of neural crest cells identifies transcription factors necessary for direct conversion of embryonic fibroblasts into neural crest cells.

    PubMed

    Motohashi, Tsutomu; Watanabe, Natsuki; Nishioka, Masahiro; Nakatake, Yuhki; Yulan, Piao; Mochizuki, Hiromi; Kawamura, Yoshifumi; Ko, Minoru S H; Goshima, Naoki; Kunisada, Takahiro

    2016-01-01

    Neural crest cells (NC cells) are multipotent cells that emerge from the edge of the neural folds and migrate throughout the developing embryo. Although the gene regulatory network for generation of NC cells has been elucidated in detail, it has not been revealed which of the factors in the network are pivotal to directing NC identity. In this study we analyzed the gene expression profile of a pure NC subpopulation isolated from Sox10-IRES-Venus mice and investigated whether these genes played a key role in the direct conversion of Sox10-IRES-Venus mouse embryonic fibroblasts (MEFs) into NC cells. The comparative molecular profiles of NC cells and neural tube cells in 9.5-day embryos revealed genes including transcription factors selectively expressed in developing trunk NC cells. Among 25 NC cell-specific transcription factor genes tested, SOX10 and SOX9 were capable of converting MEFs into SOX10-positive (SOX10+) cells. The SOX10+ cells were then shown to differentiate into neurons, glial cells, smooth muscle cells, adipocytes and osteoblasts. These SOX10+ cells also showed limited self-renewal ability, suggesting that SOX10 and SOX9 directly converted MEFs into NC cells. Conversely, the remaining transcription factors, including well-known NC cell specifiers, were unable to convert MEFs into SOX10+ NC cells. These results suggest that SOX10 and SOX9 are the key factors necessary for the direct conversion of MEFs into NC cells. PMID:26873953

  4. Protein Tyrosine Phosphatase 4A3 (PTP4A3) Is Required for Xenopus laevis Cranial Neural Crest Migration In Vivo

    PubMed Central

    Maacha, Selma; Planque, Nathalie; Laurent, Cécile; Pegoraro, Caterina; Anezo, Océane; Maczkowiak, Frédérique; Monsoro-Burq, Anne H.; Saule, Simon

    2013-01-01

    Uveal melanoma is the most common intraocular malignancy in adults, representing between about 4% and 5% of all melanomas. High expression levels of Protein Tyrosine Phosphatase 4A3, a dual phosphatase, is highly predictive of metastasis development and PTP4A3 overexpression in uveal melanoma cells increases their in vitro migration and in vivo invasiveness. Melanocytes, including uveal melanocytes, are derived from the neural crest during embryonic development. We therefore suggested that PTP4A3 function in uveal melanoma metastasis may be related to an embryonic role during neural crest cell migration. We show that PTP4A3 plays a role in cephalic neural crest development in Xenopus laevis. PTP4A3 loss of function resulted in a reduction of neural crest territory, whilst gain of function experiments increased neural crest territory. Isochronic graft experiments demonstrated that PTP4A3-depleted neural crest explants are unable to migrate in host embryos. Pharmacological inhibition of PTP4A3 on dissected neural crest cells significantly reduced their migration velocity in vitro. Our results demonstrate that PTP4A3 is required for cephalic neural crest migration in vivo during embryonic development. PMID:24376839

  5. [Intracranial fat bodies and their potential effect on brain composition and behaviour in domestic ducks with feather crests (3 case studies)].

    PubMed

    Cnotka, J; Frahm, H D; Rehkämper, G

    2006-01-01

    Intracranial fat tissue was found in the brains of three crested ducks. The three ducks differed in the size of their crest and in the volume and the location of the fat body within their brains. The duck with the large crest showed a fat body which counts for 19 % of its brain volume. Due to this fat accumulation, brain structures, mainly the cerebellum, were moved laterally. This duck had serious problems in motor coordination. Fat body of the second duck with a middle sized crest was situated in neostriatum and constituted 0,6 % of total brain volume. Additionally this duck displayed an encephalocele. The last duck did show a small crest. Its fat body was found in the area of the tentorium cerebelli and made up 17 % of its brain volume. The later two ducks were not hampered behaviourally. PMID:16475552

  6. Variability of ionospheric scintillation near the equatorial anomaly crest of the Indian zone

    NASA Astrophysics Data System (ADS)

    Chatterjee, S.; Chakraborty, S. K.

    2013-04-01

    Multistation observations of ionosphere scintillation at VHF (250 MHz) and GNSS L1 frequency from three locations - (i) Bokkhali (BOK) (geographic 21.6° N, 88.2° E, dip 31.48°, (ii) Raja Peary Mohan College Centre (RPMC) (geographic 22.66° N, 88.4° E, dip 33.5°) and (iii) Krishnath College Centre (KNC), Berhampore (geographic 24.1° N, 88.3° E, dip 35.9°) - at ~ 1° latitudinal separations near the northern crest of the equatorial ionization anomaly (EIA) of the Indian longitude sector are investigated in conjunction with total electron content (TEC) data and available ionosonde data near the magnetic equator to study fine structure in spatial and temporal variability patterns of scintillation occurrences. The observations are carried out in the autumnal equinoctial months of a high solar activity year (2011). In spite of smaller latitudinal/spatial separation among the observing stations, conspicuous differences are reflected in the onset time, duration, fade rate and fade depth of VHF scintillations as well as in spectral features. Scintillations are mostly associated with depletion in TEC around the anomaly crest and occurrence of ESF near the magnetic equator at an earlier time. Not only the strength of EIA, but also the locations of observing stations with respect to the post-sunset resurgence peak of EIA seem to play dominant role in dictating the severity of scintillation activity. A secondary enhancement in diurnal TEC in the post-sunset period seems to accentuate the irregularity activities near the anomaly crest, and a threshold value of the same may fruitfully be utilized for the prediction of scintillation around the locations. An idea regarding latitudinal extent of scintillation is developed by considering observations at L1 frequency from the GPS and GLONASS constellation of satellites. A critical value of h'F near the magnetic equator for the occurrence of simultaneous scintillation at the three centres is suggested. The observations are

  7. In Vivo Tumorigenesis Was Observed after Injection of In Vitro Expanded Neural Crest Stem Cells Isolated from Adult Bone Marrow

    PubMed Central

    Neirinckx, Virginie; Hennuy, Benoit; Swingland, James T.; Laudet, Emerence; Sommer, Lukas; Shakova, Olga; Bours, Vincent; Rogister, Bernard

    2012-01-01

    Bone marrow stromal cells are adult multipotent cells that represent an attractive tool in cellular therapy strategies. Several studies have reported that in vitro passaging of mesenchymal stem cells alters the functional and biological properties of those cells, leading to the accumulation of genetic aberrations. Recent studies described bone marrow stromal cells (BMSC) as mixed populations of cells including mesenchymal (MSC) and neural crest stem cells (NCSC). Here, we report the transformation of NCSC into tumorigenic cells, after in vitro long-term passaging. Indeed, the characterization of 6 neural crest-derived clones revealed the presence of one tumorigenic clone. Transcriptomic analyses of this clone highlighted, among others, numerous cell cycle checkpoint modifications and chromosome 11q down-regulation (suggesting a deletion of chromosome 11q) compared with the other clones. Moreover, unsupervised analysis such as a dendrogram generated after agglomerative hierarchical clustering comparing several transcriptomic data showed important similarities between the tumorigenic neural crest-derived clone and mammary tumor cell lines. Altogether, it appeared that NCSC isolated from adult bone marrow represents a potential danger for cellular therapy, and consequently, we recommend that phenotypic, functional and genetic assays should be performed on bone marrow mesenchymal and neural crest stem cells before in vivo use, to demonstrate whether their biological properties, after ex vivo expansion, remain suitable for clinical application. PMID:23071568

  8. A Phenotypic Point of View of the Adaptive Radiation of Crested Newts (Triturus cristatus Superspecies, Caudata, Amphibia).

    PubMed

    Ivanović, Ana; Džukić, Georg; Kalezić, Miloš

    2012-01-01

    The divergence in phenotype and habitat preference within the crested newt Triturus cristatus superspecies, examined across different ontogenetic stages, provides an excellent setting to explore the pattern of adaptive radiation. The crested newts form a well-supported monophyletic clade for which at least the full mitochondrial DNA phylogeny is resolved. Here we summarise studies that explored the variation in morphological (larval and adult body form, limb skeleton, and skull shape) and other phenotypic traits (early life history, developmental sequences, larval growth rate, and sexual dimorphism) to infer the magnitude and direction of evolutionary changes in crested newts. The phenotypic traits show a high level of concordance in the pattern of variation; there is a cline-like variation, from T. dobrogicus, via T. cristatus, T. carnifex, and T. macedonicus to the T. karelinii group. This pattern matches the cline of ecological preferences; T. dobrogicus is relatively aquatic, followed by T. cristatus. T. macedonicus, T. carnifex, and the T. karelinii group are relatively terrestrial. The observed pattern indicates that phenotypic diversification in crested newts emerged due to an evolutionary switch in ecological preferences. Furthermore, the pattern indicates that heterochronic changes, or changes in the timing and rate of development, underlie the observed phenotypic evolutionary diversification. PMID:22315697

  9. A Phenotypic Point of View of the Adaptive Radiation of Crested Newts (Triturus cristatus Superspecies, Caudata, Amphibia)

    PubMed Central

    Ivanović, Ana; Džukić, Georg; Kalezić, Miloš

    2012-01-01

    The divergence in phenotype and habitat preference within the crested newt Triturus cristatus superspecies, examined across different ontogenetic stages, provides an excellent setting to explore the pattern of adaptive radiation. The crested newts form a well-supported monophyletic clade for which at least the full mitochondrial DNA phylogeny is resolved. Here we summarise studies that explored the variation in morphological (larval and adult body form, limb skeleton, and skull shape) and other phenotypic traits (early life history, developmental sequences, larval growth rate, and sexual dimorphism) to infer the magnitude and direction of evolutionary changes in crested newts. The phenotypic traits show a high level of concordance in the pattern of variation; there is a cline-like variation, from T. dobrogicus, via T. cristatus, T. carnifex, and T. macedonicus to the T. karelinii group. This pattern matches the cline of ecological preferences; T. dobrogicus is relatively aquatic, followed by T. cristatus. T. macedonicus, T. carnifex, and the T. karelinii group are relatively terrestrial. The observed pattern indicates that phenotypic diversification in crested newts emerged due to an evolutionary switch in ecological preferences. Furthermore, the pattern indicates that heterochronic changes, or changes in the timing and rate of development, underlie the observed phenotypic evolutionary diversification. PMID:22315697

  10. Substrate-mediated reprogramming of human fibroblasts into neural crest stem-like cells and their applications in neural repair.

    PubMed

    Tseng, Ting-Chen; Hsieh, Fu-Yu; Dai, Niann-Tzyy; Hsu, Shan-Hui

    2016-09-01

    Cell- and gene-based therapies have emerged as promising strategies for treating neurological diseases. The sources of neural stem cells are limited while the induced pluripotent stem (iPS) cells have risk of tumor formation. Here, we proposed the generation of self-renewable, multipotent, and neural lineage-related neural crest stem-like cells by chitosan substrate-mediated gene transfer of a single factor forkhead box D3 (FOXD3) for the use in neural repair. A simple, non-toxic, substrate-mediated method was applied to deliver the naked FOXD3 plasmid into human fibroblasts. The transfection of FOXD3 increased cell proliferation and up-regulated the neural crest marker genes (FOXD3, SOX2, and CD271), stemness marker genes (OCT4, NANOG, and SOX2), and neural lineage-related genes (Nestin, β-tubulin and GFAP). The expression levels of stemness marker genes and neural crest maker genes in the FOXD3-transfected fibroblasts were maintained until the fifth passage. The FOXD3 reprogrammed fibroblasts based on the new method significantly rescued the neural function of the impaired zebrafish. The chitosan substrate-mediated delivery of naked plasmid showed feasibility in reprogramming somatic cells. Particularly, the FOXD3 reprogrammed fibroblasts hold promise as an easily accessible cellular source with neural crest stem-like behavior for treating neural diseases in the future. PMID:27341268

  11. Prevalence of antibodies to West Nile virus and other arboviruses among Crested Caracaras (Caracara cheriway) in Florida.

    PubMed

    Nemeth, Nicole M; Dwyer, James F; Morrison, Joan L; Fraser, James D

    2009-07-01

    We documented the antibody prevalence to three arboviruses, St. Louis encephalitis virus (SLEV), eastern equine encephalitis virus (EEEV), and West Nile virus (WNV), in Crested Caracaras (Caracara cheriway; n = 80) in Florida from 2007 to 2008. Antibody prevalence to WNV was higher (9%) than for the other viruses. Most seropositive birds were adults (< or =3 yr of age), with 55% of adults testing positive for antibodies to at least one virus. Adults were significantly more likely to have antibodies to WNV than nonadults (P<0.001). Prevalence of SLEV and EEEV antibodies among Crested Caracaras was 3% for each virus, and three adult caracaras had indistinguishable anti-flavivirus antibodies. The susceptibility of Crested Caracaras to adverse effects of WNV, SLEV, or EEEV infection remains unknown; however, we observed that some free-ranging individuals survived infection and successfully fledged young. Knowledge of arboviral infection among Florida's Crested Caracara, which is both state and federally threatened, is valuable considering increasing pressure on this population from rapid and extensive habitat alterations. PMID:19617494

  12. Cryptic crested newt diversity at the Eurasian transition: the mitochondrial DNA phylogeography of Near Eastern Triturus newts.

    PubMed

    Wielstra, B; Themudo, G Espregueira; Güçlü, O; Olgun, K; Poyarkov, N A; Arntzen, J W

    2010-09-01

    Crested newts of the Triturus karelinii group occur in a phylogeographically understudied region: the Near East. Controversy surrounds the systematic position of these newts within the complete crested newt assemblage (the Triturus cristatus superspecies). We explore the situation using mitochondrial sequence data (ND2 and ND4, approximately 1.7kb) and employing different methods of phylogenetic inference (Bayesian inference and Maximum Likelihood using mixed models) and molecular dating (r8s and BEAST). The T. karelinii group is monophyletic and constitutes one of four main lineages in the T. cristatus superspecies. The separation of the T. karelinii group from the remaining crested newts around 9Ma is related to the formation of the Mid-Aegean Trench, which separated the Balkan and Anatolian landmasses. The T. karelinii group comprises three geographically structured clades (eastern, central and western). The genetic divergence shown by these clades is comparable to that among recognized crested newt species. We suggest the uplift of the Armenian Plateau to be responsible for the separation of the eastern clade around 7Ma, and the re-establishment of a marine connection between the Black Sea and the Mediterranean at the end of the Messinian Salinity Crisis to have caused the split between the central and western clade around 5.5Ma. Genetic structuring within the three clades dates to the Quaternary Ice Age (<2.59Ma) and is associated with alternating periods of isolation and reconnection caused by periodic changes in sea level and surface runoff. PMID:20435147

  13. Prenuptial perfume: Alloanointing in the social rituals of the crested auklet ( Aethia cristatella) and the transfer of arthropod deterrents

    NASA Astrophysics Data System (ADS)

    Douglas, Hector D.

    2008-01-01

    Alloanointing, the transfer of chemicals between conspecifics, is known among mammals, but hitherto, the behavior has not been documented for birds. The crested auklet ( Aethia cristatella), a colonial seabird of Alaskan and Siberian waters, alloanoints during courtship with fragrant aldehydes that are released from specialized wick-like feathers located in the interscapular region. Crested auklets solicit anointment at the colony, and prospective mates rub bill, breast, head, and neck over wick feathers of their partners. This distributes aldehydes over the head, neck, and face where the birds cannot self-preen. The resulting chemical concentrations are sufficient to deter ectoparasites. Auklets that emit more odorant can transfer more defensive chemicals to mates and are thus more sexually attractive. Behavioral studies showed that crested auklets are attracted to their scent. Wild birds searched for dispensers that emitted their scent and rubbed their bills on the dispensers and engaged in vigorous anointment behaviors. In captive experiments, naïve crested auklets responded more strongly to synthetic auklet scent than controls, and the greatest behavioral response occurred during early courtship. This study extends scientific knowledge regarding functions of alloanointing. Alloanointing had previously been attributed to scent marking and individual recognition in vertebrates. Alloanointing is described here in the context of an adaptive social cue — the transfer of arthropod deterrents between prospective mates.

  14. In vivo tumorigenesis was observed after injection of in vitro expanded neural crest stem cells isolated from adult bone marrow.

    PubMed

    Wislet-Gendebien, Sabine; Poulet, Christophe; Neirinckx, Virginie; Hennuy, Benoit; Swingland, James T; Laudet, Emerence; Sommer, Lukas; Shakova, Olga; Bours, Vincent; Rogister, Bernard

    2012-01-01

    Bone marrow stromal cells are adult multipotent cells that represent an attractive tool in cellular therapy strategies. Several studies have reported that in vitro passaging of mesenchymal stem cells alters the functional and biological properties of those cells, leading to the accumulation of genetic aberrations. Recent studies described bone marrow stromal cells (BMSC) as mixed populations of cells including mesenchymal (MSC) and neural crest stem cells (NCSC). Here, we report the transformation of NCSC into tumorigenic cells, after in vitro long-term passaging. Indeed, the characterization of 6 neural crest-derived clones revealed the presence of one tumorigenic clone. Transcriptomic analyses of this clone highlighted, among others, numerous cell cycle checkpoint modifications and chromosome 11q down-regulation (suggesting a deletion of chromosome 11q) compared with the other clones. Moreover, unsupervised analysis such as a dendrogram generated after agglomerative hierarchical clustering comparing several transcriptomic data showed important similarities between the tumorigenic neural crest-derived clone and mammary tumor cell lines. Altogether, it appeared that NCSC isolated from adult bone marrow represents a potential danger for cellular therapy, and consequently, we recommend that phenotypic, functional and genetic assays should be performed on bone marrow mesenchymal and neural crest stem cells before in vivo use, to demonstrate whether their biological properties, after ex vivo expansion, remain suitable for clinical application. PMID:23071568

  15. INHIBITION OF NEURAL CREST CELL MIGRATION BY THE WATER DISINFECTION BYPRODUCTS DICHLORO-, DIBROMO-, AND BROMOCHLORO-ACETIC ACID.

    EPA Science Inventory

    INHIBITION OF NEURAL CREST CELL MIGRATION BY THE WATER DISINFECTION BYPRODUCTS DICHLORO-, DIBROMO- AND BROMOCHLORO-ACETIC ACID. JE Andrews, H Nichols, J Schmid 1, and ES Hunter. Reproductive Toxicology Division, 1Research Support Division, NHEERL, USEPA, RTP, NC, USA.

    ...

  16. The Lamprey: A jawless vertebrate model system for examining origin of the neural crest and other vertebrate traits

    PubMed Central

    Green, Stephen A.; Bronner, Marianne E.

    2014-01-01

    Summary Lampreys are a group of jawless fishes that serve as an important point of comparison for studies of vertebrate evolution. Lampreys and hagfishes are agnathan fishes, the cyclostomes, which sit at a crucial phylogenetic position as the only living sister group of the jawed vertebrates. Comparisons between cyclostomes and jawed vertebrates can help identify shared derived (i.e. synapomorphic) traits that might have been inherited from ancestral early vertebrates, if unlikely to have arisen convergently by chance. One example of a uniquely vertebrate trait is the neural crest, an embryonic tissue that produces many cell types crucial to vertebrate features, such as the craniofacial skeleton, pigmentation of the skin, and much of the peripheral nervous system (Gans and Northcutt, 1983). Invertebrate chordates arguably lack unambiguous neural crest homologs, yet have cells with some similarities, making comparisons with lampreys and jawed vertebrates essential for inferring characteristics of development in early vertebrates, and how they may have evolved from nonvertebrate chordates. Here we review recent research on cyclostome neural crest development, including research on lamprey gene regulatory networks and differentiated neural crest fates. PMID:24560767

  17. Neural crest and Schwann cell progenitor-derived melanocytes are two spatially segregated populations similarly regulated by Foxd3

    PubMed Central

    Nitzan, Erez; Pfaltzgraff, Elise R.; Labosky, Patricia A.; Kalcheim, Chaya

    2013-01-01

    Skin melanocytes arise from two sources: either directly from neural crest progenitors or indirectly from neural crest-derived Schwann cell precursors after colonization of peripheral nerves. The relationship between these two melanocyte populations and the factors controlling their specification remains poorly understood. Direct lineage tracing reveals that neural crest and Schwann cell progenitor-derived melanocytes are differentially restricted to the epaxial and hypaxial body domains, respectively. Furthermore, although both populations are initially part of the Foxd3 lineage, hypaxial melanocytes lose Foxd3 at late stages upon separation from the nerve, whereas we recently found that epaxial melanocytes segregate earlier from Foxd3-positive neural progenitors while still residing in the dorsal neural tube. Gain- and loss-of-function experiments in avians and mice, respectively, reveal that Foxd3 is both sufficient and necessary for regulating the balance between melanocyte and Schwann cell development. In addition, Foxd3 is also sufficient to regulate the switch between neuronal and glial fates in sensory ganglia. Together, we propose that differential fate acquisition of neural crest-derived cells depends on their progressive segregation from the Foxd3-positive lineage. PMID:23858437

  18. "A taste for the beautiful": latent aesthetic mate preferences for white crests in two species of Australian grassfinches.

    PubMed

    Burley, N T; Symanski, R

    1998-12-01

    Darwin first hypothesized that bright colors and elaborate ornamentation of male animals evolved in response to the "aesthetic" mate preferences of females. By this reasoning, potentially costly male secondary sexual traits may evolve not in response to selection for demonstration of vigor but, rather, in response to latent, nonfunctional preferences by females. Recent comparative evidence for this phenomenon is equivocal. Here we present experimental evidence that two avian species from a lineage devoid of crested species have mate preferences for opposite sex conspecifics wearing artificial white crests. Other colors of crests that have been studied are not preferred. Preferences for white crests did not diminish over the longest experimental interval (12 wk). These results are additional powerful evidence for highly structured aesthetic mate preferences in estrildine finches. Sex differences in the expression of preferences, and the widespread occurrence of facial ornamentation in birds, suggest that the preference "structure" is influenced by the central nervous system. We hypothesize that aesthetic preferences are a potent force in the early evolution of sexually selected traits, and that "indicator" traits evolve secondarily from traits initially favored by aesthetic preferences. PMID:18811428

  19. Relationship between spatially restricted Krox-20 gene expression in branchial neural crest and segmentation in the chick embryo hindbrain.

    PubMed Central

    Nieto, M A; Sechrist, J; Wilkinson, D G; Bronner-Fraser, M

    1995-01-01

    Previous studies have suggested that the rostrocaudal patterning of branchial arches in the vertebrate embryo derives from a coordinate segmental specification of gene expression in rhombomeres (r) and neural crest. However, expression of the Krox-20 gene is restricted to neural crest cells migrating to the third branchial arch, apparently from r5, whereas this rhombomere contributes cells to both the second and third arches. We examined in the chick embryo how this spatially restricted expression is established. Expression occurs in precursors in both r5 and r6, and we show by cell labelling that both rhombomeres contribute to Krox-20-expressing neural crest, emigration occurring first from r6 and later caudally from r5. Krox-20 transcripts are not detected in some precursors in rostral r5, presaging the lack of expression in cells migrating rostrally from this rhombomere. After transposition of r6 to the position of r4 or r5, many Krox-20-expressing cells migrate rostral to the otic vesicle, whereas when r5 is transplanted to the position of r4, only a small number of migrating cells express Krox-20. These results indicate that, in the chick, Krox-20 expression in branchial neural crest does not correlate with rhombomeric segmentation, and that there may be intrinsic differences in regulation between the r5 and r6 Krox-20-expressing populations. Images PMID:7537662

  20. CREST biorepository for translational studies on malignant mesothelioma, lung cancer and other respiratory tract diseases: Informatics infrastructure and standardized annotation

    PubMed Central

    UGOLINI, DONATELLA; NERI, MONICA; BENNATI, LUCA; CANESSA, PIER ALDO; CASANOVA, GEORGIA; LANDO, CECILIA; LEONCINI, GIACOMO; MARRONI, PAOLA; PARODI, BARBARA; SIMONASSI, CLAUDIO; BONASSI, STEFANO

    2012-01-01

    Advances in molecular epidemiology and translational research have led to the need for biospecimen collection. The Cancer of the Respiratory Tract (CREST) biorepository is concerned with pleural malignant mesothelioma (MM) and lung cancer (LC). The biorepository staff has collected demographic and epidemiological data directly from consenting subjects using a structured questionnaire, in agreement with The Public Population Project in Genomics (P3G). Clinical and follow-up data were collected. Sample data were also recorded. The architecture is based on a database designed with Microsoft Access. Data standardization was carried out to conform with established conventions or procedures. As from January 31, 2011, the overall number of recruited subjects was 1,857 (454 LC, 245 MM, 130 other cancers and 1,028 controls). Due to its infrastructure, CREST was able to join international projects, sharing samples and/or data with other research groups in the field. The data management system allows CREST to be involved, through a minimum data set, in the national project for the construction of the Italian network of Oncologic BioBanks (RIBBO), and in the infrastructure of a pan-European biobank network (BBMRI). The CREST biorepository is a valuable tool for translational studies on respiratory tract diseases, because of its simple and efficient infrastructure. PMID:22969926

  1. TOOLS FOR DESIGN, CALIBRATION, CONSTRUCTION AND USE OF LONG-THROATED FLUMES AND BROAD-CRESTED WEIRS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-throated flumes and broad-crested weirs provide a practical, low-cost, flexible means of measuring open-channel flows in new and existing irrigation systems and have distinct advantages over other flume and weir devices. Application of these flumes and weirs has been greatly facilitated by the...

  2. Complete Genome Sequence of Avian Paramyxovirus Strain APMV-6/red-crested pochard/Balkhash/5842/2013 from Kazakhstan

    PubMed Central

    Kydyrmanov, Aidyn; Seidalina, Aigerim; Jenckel, Maria; Starick, Elke; Grund, Christian; Asanova, Saule; Khan, Elizaveta; Daulbayeva, Klara; Kasymbekov, Yermukhammet; Zhumatov, Kainar; Sayatov, Marat; Beer, Martin

    2015-01-01

    An avian paramyxovirus 6 strain was isolated during a wild bird monitoring study in Kazakhstan in 2013. The virus was isolated from a wild duck red-crested pochard (Netta rufina) in southeastern Kazakhstan. Here, we present the complete genome sequence of the virus. PMID:26184926

  3. Gastrointestinal Helminth Parasites of Double-Crested Cormorants (Phalacrocorax auritus) at Four Sites in Saskatchewan, Canada, 2006-2007.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined the gastrointestinal parasite fauna of adult double-crested cormorants from breeding colonies on four very different lakes spanning a major ecotone from prairie to boreal forest in Saskatchewan, Canada. Our objectives were to document regional parasite fauna, and identify potential diff...

  4. Waterbird numbers and double-crested cormorants movement patterns within aquaculture production areas of the lower Mississippi River, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the past seven consecutive years (1999-2007), aerial surveys by fixed-wing aircraft were conducted to monitor and quantify the wintering cormorant numbers. In addition, during the past two winters 2005-2006 and 2006-2007, 20 double-crested cormorants were captured, leg banded, and fitted wit...

  5. Leader Cells Define Directionality of Trunk, but Not Cranial, Neural Crest Cell Migration.

    PubMed

    Richardson, Jo; Gauert, Anton; Briones Montecinos, Luis; Fanlo, Lucía; Alhashem, Zainalabdeen Mohmammed; Assar, Rodrigo; Marti, Elisa; Kabla, Alexandre; Härtel, Steffen; Linker, Claudia

    2016-05-31

    Collective cell migration is fundamental for life and a hallmark of cancer. Neural crest (NC) cells migrate collectively, but the mechanisms governing this process remain controversial. Previous analyses in Xenopus indicate that cranial NC (CNC) cells are a homogeneous population relying on cell-cell interactions for directional migration, while chick embryo analyses suggest a heterogeneous population with leader cells instructing directionality. Our data in chick and zebrafish embryos show that CNC cells do not require leader cells for migration and all cells present similar migratory capacities. In contrast, laser ablation of trunk NC (TNC) cells shows that leader cells direct movement and cell-cell contacts are required for migration. Moreover, leader and follower identities are acquired before the initiation of migration and remain fixed thereafter. Thus, two distinct mechanisms establish the directionality of CNC cells and TNC cells. This implies the existence of multiple molecular mechanisms for collective cell migration. PMID:27210753

  6. CRANIAL NEURAL CREST CELLS ON THE MOVE: THEIR ROLES IN CRANIOFACIAL DEVELOPMENT

    PubMed Central

    Cordero, Dwight R.; Brugmann, Samantha; Chu, Yvonne; Bajpai, Ruchi; Jame, Maryam; Helms, Jill A.

    2010-01-01

    The craniofacial region is assembled through the active migration of cells and the rearrangement and sculpting of facial prominences and pharyngeal arches, which consequently make it particularly susceptible to a large number of birth defects. Genetic, molecular, and cellular processes must be temporally and spatially regulated to culminate in the three-dimension structures of the face. The starting constituent for the majority of skeletal and connective tissues in the face is a pluripotent population of cells, the cranial neural crest cells (NCCs). In this review we discuss the newest scientific findings in the development of the craniofacial complex as related to NCCs. Furthermore, we present recent findings on NCC diseases called neurocristopathies and, in doing so, provide clinicians with new tools for understanding a growing number of craniofacial genetic disorders. PMID:21271641

  7. Coastal defence through low crested breakwater structures: jumping out of the frying pan into the fire?

    PubMed

    Munari, Cristina; Corbau, Corinne; Simeoni, Umberto; Mistri, Michele

    2011-08-01

    The Adriatic coast of Punta Marina (Ravenna) is protected by 3-km long low crested breakwater structures (LCSs). Through a 3-years long multidisciplinar study, we assessed the impact of such defensive structures on environmental and biological condition. LCSs create pools where conditions are very different from the surrounding nearshore system. Mechanical disturbance by currents and waves varied greatly in intensity and frequency between seaward and landward sides of the structures. Sedimentary budget was positive at the landward side, but it was due to a gain on the seafloor and not on the emerged beach. The budget at seaward was negative. LCSs determine differences in benthic assemblages, alter the seasonal pattern of communities, and modify seasonal fluctuations of animal assemblages. Landward sheltered areas can be seen as "lagoonal island" surrounded by a "sea of marine habitat". Differences in ecological quality status, obtained through M-AMBI, are due to the sum of these factors. PMID:21722927

  8. Nymphal Linguatulosis in Indian Crested Porcupines (Histrix Indica) in Southwest of Iran

    PubMed Central

    Rajabloo, Mohammad; Razavi, Seyed Mostafa; Shayegh, Hossein; Alavi, Amir Mootabi

    2015-01-01

    Linguatula serrata is one of the important zoonotic parasites. Carnivores serve as definitive host. The larvae existed in mesenteric lymph nodes (MLNs), liver, lungs, etc of intermediate herbivores. The definitive host becomes infected by ingesting viscera containing the infective nymphal stage. Humans may be infected with Linguatula either by ingestion of nymphs resulting in a condition called nasopharyngeal linguatulosis or Halzoun syndrome or by ingestion of infective eggs which develop in internal organs resulting in visceral linguatulosis. Indian crested porcupine (Hystrix indica) is a common rodent in Middle East. Based on some tradition, consumption of Histrix meat and viscera is common in some parts of Iran. The present study reports the occurrence of Linguatula serrata nymph in H. indica as a new intermediate host from southwest of Iran. PMID:26114151

  9. Nymphal Linguatulosis in Indian Crested Porcupines (Histrix Indica) in Southwest of Iran.

    PubMed

    Rajabloo, Mohammad; Razavi, Seyed Mostafa; Shayegh, Hossein; Alavi, Amir Mootabi

    2015-06-01

    Linguatula serrata is one of the important zoonotic parasites. Carnivores serve as definitive host. The larvae existed in mesenteric lymph nodes (MLNs), liver, lungs, etc of intermediate herbivores. The definitive host becomes infected by ingesting viscera containing the infective nymphal stage. Humans may be infected with Linguatula either by ingestion of nymphs resulting in a condition called nasopharyngeal linguatulosis or Halzoun syndrome or by ingestion of infective eggs which develop in internal organs resulting in visceral linguatulosis. Indian crested porcupine (Hystrix indica) is a common rodent in Middle East. Based on some tradition, consumption of Histrix meat and viscera is common in some parts of Iran. The present study reports the occurrence of Linguatula serrata nymph in H. indica as a new intermediate host from southwest of Iran. PMID:26114151

  10. Molecular Control of the Neural Crest and Peripheral Nervous System Development

    PubMed Central

    Newbern, Jason M.

    2015-01-01

    A transient and unique population of multipotent stem cells, known as neural crest cells (NCCs), generate a bewildering array of cell types during vertebrate development. An attractive model among developmental biologists, the study of NCC biology has provided a wealth of knowledge regarding the cellular and molecular mechanisms important for embryogenesis. Studies in numerous species have defined how distinct phases of NCC specification, proliferation, migration, and survival contribute to the formation of multiple functionally distinct organ systems. NCC contributions to the peripheral nervous system (PNS) are well known. Critical developmental processes have been defined that provide outstanding models for understanding how extracellular stimuli, cell–cell interactions, and transcriptional networks cooperate to direct cellular diversification and PNS morphogenesis. Dissecting the complex extracellular and intracellular mechanisms that mediate the formation of the PNS from NCCs may have important therapeutic implications for neurocristopathies, neuropathies, and certain forms of cancer. PMID:25662262

  11. Cranial neural crest cells on the move: their roles in craniofacial development.

    PubMed

    Cordero, Dwight R; Brugmann, Samantha; Chu, Yvonne; Bajpai, Ruchi; Jame, Maryam; Helms, Jill A

    2011-02-01

    The craniofacial region is assembled through the active migration of cells and the rearrangement and sculpting of facial prominences and pharyngeal arches, which consequently make it particularly susceptible to a large number of birth defects. Genetic, molecular, and cellular processes must be temporally and spatially regulated to culminate in the three-dimension structures of the face. The starting constituent for the majority of skeletal and connective tissues in the face is a pluripotent population of cells, the cranial neural crest cells (NCCs). In this review we discuss the newest scientific findings in the development of the craniofacial complex as related to NCCs. Furthermore, we present recent findings on NCC diseases called neurocristopathies and, in doing so, provide clinicians with new tools for understanding a growing number of craniofacial genetic disorders. PMID:21271641

  12. Effects of contaminants on Double-crested Cormorant reproduction in Green Bay, Wisconsin, USA

    USGS Publications Warehouse

    Custer, T.W.; Custer, Christine M.; Stromborg, K.L.; Melancon, M.J.

    1998-01-01

    In 1994 and 1995, Double-crested Cormorants Phalacrocorax auritus were monitored from egg-laying through 12 days of age at Cat Island, Green Bay, Wisconsin, USA. Sample eggs at hatching were analysed for organochlorines (including total PCBs, PCB congeners, and DDE), hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity in livers of embryos, and eggshell thickness. The number of eggs per nest that hatched and survived to i 2 days of age was estimated to be 2.2 in 1994 and 2.0 in 1995. Hatching success of eggs was not correlated with PCBs, the toxicity of PCBs based on congeners, or EROD activity. Hatching success was correlated with eggshell thickness and negatively correlated with DDE concentrations. Even though the insecticide DDT was banned in the early 1970s, we suggest that DDE concentrations in cormorant eggs in Green Bay are still having an affect on reproduction in this species.

  13. Effects of contaminants on Double-crested Cormorant reproduction in Green Bay, Wisconsin, USA

    USGS Publications Warehouse

    Custer, T.W.; Custer, Christine M.; Stromborg, K.L.; Melancon, M.J.

    1999-01-01

    In 1994 and 1995, Double-crested Cormorants Phalacrocorax auritus were monitored from egg-laying through 12 days of age at Cat Island, Green Bay, Wisconsin, USA. Sample eggs at hatching were analysed for organochlorines (including total PCBs, PCB congeners, and DDE), hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity in livers of embryos, and eggshell thickness. The number of eggs per nest that hatched and survived to i 2 days of age was estimated to be 2.2 in 1994 and 2.0 in 1995. Hatching success of eggs was not correlated with PCBs, the toxicity of PCBs based on congeners, or EROD activity. Hatching success was correlated with eggshell thickness and negatively correlated with DDE concentrations. Even though the insecticide DDT was banned in the early 1970s, we suggest that DDE concentrations in cormorant eggs in Green Bay are still having an affect on reproduction in this species.

  14. Tcf7l1 protects the anterior neural fold from adopting the neural crest fate.

    PubMed

    Mašek, Jan; Machoň, Ondřej; Kořínek, Vladimír; Taketo, M Mark; Kozmik, Zbyněk

    2016-06-15

    The neural crest (NC) is crucial for the evolutionary diversification of vertebrates. NC cells are induced at the neural plate border by the coordinated action of several signaling pathways, including Wnt/β-catenin. NC cells are normally generated in the posterior neural plate border, whereas the anterior neural fold is devoid of NC cells. Using the mouse model, we show here that active repression of Wnt/β-catenin signaling is required for maintenance of neuroepithelial identity in the anterior neural fold and for inhibition of NC induction. Conditional inactivation of Tcf7l1, a transcriptional repressor of Wnt target genes, leads to aberrant activation of Wnt/β-catenin signaling in the anterior neuroectoderm and its conversion into NC. This reduces the developing prosencephalon without affecting the anterior-posterior neural character. Thus, Tcf7l1 defines the border between the NC and the prospective forebrain via restriction of the Wnt/β-catenin signaling gradient. PMID:27302397

  15. Feeding flights of breeding double-crested cormorants at two Wisconsin colonies

    USGS Publications Warehouse

    Custer, T.W.; Bunck, C.

    1992-01-01

    Unmarked Double-crested Cormorants (Phalacrocorax auritus) (n = 523) were followed by airplane from Cat Island and Spider Island, two nesting colonies in Wisconsin, to their first landing site. Cormorants flew an average of 2.0 km from Cat Island (maximum 40 km) and 2.4 km from Spider Island (maximum12 km). The mean direction of landing sites differed seasonally for fights from Spider Island, but not from Cat Island. Cormorants generally landed in Green Bay or Lake Michigan (>99%) and rarely landed in inland lakes or ponds. The most frequent (> 80%) water depth at landing sites for each colony was 9.l m were used less frequently than available within the maximum observed flight distance for each colony. The average flight speed for cormorants was 61 km/h.

  16. Feeding flights of breeding double-crested cormorants at two Wisconsin colonies

    USGS Publications Warehouse

    Custer, T.W.; Bunck, C.

    1992-01-01

    Unmarked Double-crested Cormorants (Phalacrocorax auritus ) were followed by airplane from Cat Island and Spider Island, two nesting colonies in Wisconsin, to their first landing site. Cormorants flew an average of 2.0 km from Cat Island (maximum 40 km) and 2.4 km from Spider Island (maximum 12 km). The mean direction of landing sites differed seasonally for flights from Spider Island, but not from Cat Island, Cormorants generally landed in Green Bay or Lake Michigan and rarely landed in inland lakes or ponds. The most frequent water depth at landing sites for each colony was < 9.1 m. Water depths greater than or equal to 9.1 m were used less frequently than available within the maximum observed flight distance for each colony. The average flight speed for cormorants was 61 km/h.

  17. Hand1 phosphoregulation within the distal arch neural crest is essential for craniofacial morphogenesis.

    PubMed

    Firulli, Beth A; Fuchs, Robyn K; Vincentz, Joshua W; Clouthier, David E; Firulli, Anthony B

    2014-08-01

    In this study we examine the consequences of altering Hand1 phosphoregulation in the developing neural crest cells (NCCs) of mice. Whereas Hand1 deletion in NCCs reveals a nonessential role for Hand1 in craniofacial development and embryonic survival, altering Hand1 phosphoregulation, and consequently Hand1 dimerization affinities, in NCCs results in severe mid-facial clefting and neonatal death. Hand1 phosphorylation mutants exhibit a non-cell-autonomous increase in pharyngeal arch cell death accompanied by alterations in Fgf8 and Shh pathway expression. Together, our data indicate that the extreme distal pharyngeal arch expression domain of Hand1 defines a novel bHLH-dependent activity, and that disruption of established Hand1 dimer phosphoregulation within this domain disrupts normal craniofacial patterning. PMID:25053435

  18. Bill malformations in double-crested cormorants with low exposure to organochlorines

    SciTech Connect

    Kuiken, T.; Fox, G.A.; Danesik, K.L.

    1999-12-01

    Eight of 20 newly hatched double-crested cormorants (Phalacrocorax auritus), captured at Dore Lake (Saskatchewan, Canada) and raised in captivity, developed malformed bills when they were 2 to 3 weeks old. Malformation was characterized by abnormal flexure and rotation of the maxilla and mandible, resulting in a crossed bill. By radiography, the premaxillary and dental bones were misshapen. Morphologically similar malformed bills in free-living comorants have been attributed to exposure to polyhalogenated aromatic hydrocarbons. However, the concentrations of total PCBs in the livers of these captive cormorants with malformed bills and in their diet were lower than have been previously associated with such malformations and were considered too low to have been the cause. The bill malformations may have been caused by deficiency of vitamin D{sub 3}, because the cormorants were kept indoors without exposure to ultraviolet light and were fed frozen fish that may have been deficient in this vitamin.

  19. Tensor Facia Lata-iliac crest osteocutaneous flap for orbitomaxillary reconstruction: A preliminary report

    PubMed Central

    Iyer, Subramania; Kuriakose, Moni A.

    2010-01-01

    Tensor Fascia Lata muscle and musculocutaneous flap has been used in the past for reconstruction of trunk defects and also as a free flap for soft tissue reconstruction elsewhere in the body. Transferring the iliac crest along with the muscle as a free flap has been described earlier, reported for bridging calcaneal defect and small mandibular defects. The use of this flap as a source of free vascularised bone has not been widely practised since these initial few reports. Anatomical studies were carried out to assess the feasibility of using this flap for reconstructing maxillary and other head and neck defects, following which it was successfully used for these indications. The preliminary report describes the flap anatomy, method of harvest and its potential uses in head and neck reconstruction. PMID:20924442

  20. Cranial muscles in amphibians: development, novelties and the role of cranial neural crest cells

    PubMed Central

    Schmidt, Jennifer; Piekarski, Nadine; Olsson, Lennart

    2013-01-01

    Our research on the evolution of the vertebrate head focuses on understanding the developmental origins of morphological novelties. Using a broad comparative approach in amphibians, and comparisons with the well-studied quail-chicken system, we investigate how evolutionarily conserved or variable different aspects of head development are. Here we review research on the often overlooked development of cranial muscles, and on its dependence on cranial cartilage development. In general, cranial muscle cell migration and the spatiotemporal pattern of cranial muscle formation appears to be very conserved among the few species of vertebrates that have been studied. However, fate-mapping of somites in the Mexican axolotl revealed differences in the specific formation of hypobranchial muscles (tongue muscles) in comparison to the chicken. The proper development of cranial muscles has been shown to be strongly dependent on the mostly neural crest-derived cartilage elements in the larval head of amphibians. For example, a morpholino-based knock-down of the transcription factor FoxN3 in Xenopus laevis has drastic indirect effects on cranial muscle patterning, although the direct function of the gene is mostly connected to neural crest development. Furthermore, extirpation of single migratory streams of cranial neural crest cells in combination with fate-mapping in a frog shows that individual cranial muscles and their neural crest-derived connective tissue attachments originate from the same visceral arch, even when the muscles attach to skeletal components that are derived from a different arch. The same pattern has also been found in the chicken embryo, the only other species that has been thoroughly investigated, and thus might be a conserved pattern in vertebrates that reflects the fundamental nature of a mechanism that keeps the segmental order of the head in place despite drastic changes in adult anatomy. There is a need for detailed comparative fate-mapping of pre

  1. A zebrafish melanoma model reveals emergence of neural crest identity during melanoma initiation.

    PubMed

    Kaufman, Charles K; Mosimann, Christian; Fan, Zi Peng; Yang, Song; Thomas, Andrew J; Ablain, Julien; Tan, Justin L; Fogley, Rachel D; van Rooijen, Ellen; Hagedorn, Elliott J; Ciarlo, Christie; White, Richard M; Matos, Dominick A; Puller, Ann-Christin; Santoriello, Cristina; Liao, Eric C; Young, Richard A; Zon, Leonard I

    2016-01-29

    The "cancerized field" concept posits that cancer-prone cells in a given tissue share an oncogenic mutation, but only discreet clones within the field initiate tumors. Most benign nevi carry oncogenic BRAF(V600E) mutations but rarely become melanoma. The zebrafish crestin gene is expressed embryonically in neural crest progenitors (NCPs) and specifically reexpressed in melanoma. Live imaging of transgenic zebrafish crestin reporters shows that within a cancerized field (BRAF(V600E)-mutant; p53-deficient), a single melanocyte reactivates the NCP state, revealing a fate change at melanoma initiation in this model. NCP transcription factors, including sox10, regulate crestin expression. Forced sox10 overexpression in melanocytes accelerated melanoma formation, which is consistent with activation of NCP genes and super-enhancers leading to melanoma. Our work highlights NCP state reemergence as a key event in melanoma initiation. PMID:26823433

  2. Solar cycle variation of the total electron content around equatorial anomaly crest region in east asia

    NASA Astrophysics Data System (ADS)

    Huang, Yinn-Nien; Cheng, Kang

    1995-10-01

    The monthly mean hourly values of total electron content data obtained at Lunping Observatory (geographic coordinates 25.00°N, 121.17°E; geomagnetic coordinates 14.3°N, 191.3°E) by using the ETS2 satellite beacon signal during the period from March 1977 to December 1990 have been used to analyze the solar cycle variations of total electron content (TEC) around equatorial anomaly crest region in East Asia. Positive, correlations were found between the 12 month running average of monthly mean TECs and sunspot numbers. By using the linear regression analysis method, the contour charts for real diurnal and seasonal variations of TEC at certain sunspot numbers were constructed and described. The diurnal variation of TEC was represented by the sum of its diurnal mean and first three harmonic components. The solar cycle variations of these components have also been discussed.

  3. Brown skin disease: A syndrome of dysecdysis in Puerto Rican crested toads (Peltophryne lemur).

    PubMed

    Crawshaw, Graham; Pienkowski, Maria; Lentini, Andrew; Dutton, Christopher; Delnatte, Pauline; Russell, Deanna; Berkvens, Charlene; Barker, Ian; Smith, Dale

    2014-01-01

    The endangered Puerto Rican crested toad (Peltophryne [Bufo] lemur) has been held and bred in zoos for release into protected areas in Puerto Rico since 1982. In 2004, several cases of a novel syndrome of skin changes in toads were noticed at the Toronto Zoo. A total of 21 toads were found to have similar lesions and the condition has been seen in several other groups of toads in subsequent years. Affected toads show an uncharacteristic sheen of dark-brown leathery skin, followed by recurring dysecdysis, reduced appetite, weight loss, and death from secondary causes. Histologically the condition is characterized by epithelial hyperplasia and hyperkeratosis, ulceration, and the presence of superficial mats of bacterial and fungal agents. No etiology has been identified and to date toads have not permanently responded to treatment with various pharmaceutical and nutritional therapies. PMID:25234808

  4. Cranial Neural Crest Cell Contribution to Craniofacial Formation, Pathology, and Future Directions in Tissue Engineering

    PubMed Central

    Snider, Taylor Nicholas; Mishina, Yuji

    2015-01-01

    This review provides an overview of the state and future directions of development and pathology in the craniofacial complex in the context of Cranial Neural Crest Cells (CNCC). CNCC are a multipotent cell population that is largely responsible for forming the vertebrate head. We focus on findings that have increased the knowledge of gene regulatory networks and molecular mechanisms governing CNCC migration and the participation of these cells in tissue formation. Pathology due to aberrant migration or cell death of CNCC, termed neurocristopathies, is discussed in addition to craniosynostoses. Finally, we discuss tissue engineering applications that take advantage of recent advancements in genome editing and the multipotent nature of CNCC. These applications have relevance to treating diseases due directly to the failure of CNCC, and also in restoring tissues lost due to a variety of reasons. PMID:25227212

  5. In vivo time-lapse imaging reveals extensive neural crest and endothelial cell interactions during neural crest migration and formation of the dorsal root and sympathetic ganglia.

    PubMed

    George, Lynn; Dunkel, Haley; Hunnicutt, Barbara J; Filla, Michael; Little, Charles; Lansford, Rusty; Lefcort, Frances

    2016-05-01

    During amniote embryogenesis the nervous and vascular systems interact in a process that significantly affects the respective morphogenesis of each network by forming a "neurovascular" link. The importance of neurovascular cross-talk in the central nervous system has recently come into focus with the growing awareness that these two systems interact extensively both during development, in the stem-cell niche, and in neurodegenerative conditions such as Alzheimer's Disease and Amyotrophic Lateral Sclerosis. With respect to the peripheral nervous system, however, there have been no live, real-time investigations of the potential relationship between these two developing systems. To address this deficit, we used multispectral 4D time-lapse imaging in a transgenic quail model in which endothelial cells (ECs) express a yellow fluorescent marker, while neural crest cells (NCCs) express an electroporated red fluorescent marker. We monitored EC and NCC migration in real-time during formation of the peripheral nervous system. Our time-lapse recordings indicate that NCCs and ECs are physically juxtaposed and dynamically interact at multiple locations along their trajectories. These interactions are stereotypical and occur at precise anatomical locations along the NCC migratory pathway. NCCs migrate alongside the posterior surface of developing intersomitic vessels, but fail to cross these continuous streams of motile ECs. NCCs change their morphology and migration trajectory when they encounter gaps in the developing vasculature. Within the nascent dorsal root ganglion, proximity to ECs causes filopodial retraction which curtails forward persistence of NCC motility. Overall, our time-lapse recordings support the conclusion that primary vascular networks substantially influence the distribution and migratory behavior of NCCs and the patterned formation of dorsal root and sympathetic ganglia. PMID:26988118

  6. The neural crest lineage as a driver of disease heterogeneity in Tuberous Sclerosis Complex and Lymphangioleiomyomatosis

    PubMed Central

    Delaney, Sean P.; Julian, Lisa M.; Stanford, William L.

    2014-01-01

    Lymphangioleiomyomatosis (LAM) is a rare neoplastic disease, best characterized by the formation of proliferative nodules that express smooth muscle and melanocytic antigens within the lung parenchyma, leading to progressive destruction of lung tissue and function. The pathological basis of LAM is associated with Tuberous Sclerosis Complex (TSC), a multi-system disorder marked by low-grade tumors in the brain, kidneys, heart, eyes, lung and skin, arising from inherited or spontaneous germ-line mutations in either of the TSC1 or TSC2 genes. LAM can develop either in a patient with TSC (TSC-LAM) or spontaneously (S-LAM), and it is clear that the majority of LAM lesions of both forms are characterized by an inactivating mutation in either TSC1 or TSC2, as in TSC. Despite this genetic commonality, there is considerable heterogeneity in the tumor spectrum of TSC and LAM patients, the basis for which is currently unknown. There is extensive clinical evidence to suggest that the cell of origin for LAM, as well as many of the TSC-associated tumors, is a neural crest cell, a highly migratory cell type with extensive multi-lineage potential. Here we explore the hypothesis that the types of tumors that develop and the tissues that are affected in TSC and LAM are dictated by the developmental timing of TSC gene mutations, which determines the identities of the affected cell types and the size of downstream populations that acquire a mutation. We further discuss the evidence to support a neural crest origin for LAM and TSC tumors, and propose approaches for generating humanized models of TSC and LAM that will allow cell of origin theories to be experimentally tested. Identifying the cell of origin and developing appropriate humanized models is necessary to truly understand LAM and TSC pathology and to establish effective and long-lasting therapeutic approaches for these patients. PMID:25505789

  7. Human epidermal neural crest stem cells as a source of Schwann cells

    PubMed Central

    Sakaue, Motoharu; Sieber-Blum, Maya

    2015-01-01

    We show that highly pure populations of human Schwann cells can be derived rapidly and in a straightforward way, without the need for genetic manipulation, from human epidermal neural crest stem cells [hEPI-NCSC(s)] present in the bulge of hair follicles. These human Schwann cells promise to be a useful tool for cell-based therapies, disease modelling and drug discovery. Schwann cells are glia that support axons of peripheral nerves and are direct descendants of the embryonic neural crest. Peripheral nerves are damaged in various conditions, including through trauma or tumour-related surgery, and Schwann cells are required for their repair and regeneration. Schwann cells also promise to be useful for treating spinal cord injuries. Ex vivo expansion of hEPI-NCSC isolated from hair bulge explants, manipulating the WNT, sonic hedgehog and TGFβ signalling pathways, and exposure of the cells to pertinent growth factors led to the expression of the Schwann cell markers SOX10, KROX20 (EGR2), p75NTR (NGFR), MBP and S100B by day 4 in virtually all cells, and maturation was completed by 2 weeks of differentiation. Gene expression profiling demonstrated expression of transcripts for neurotrophic and angiogenic factors, as well as JUN, all of which are essential for nerve regeneration. Co-culture of hEPI-NCSC-derived human Schwann cells with rodent dorsal root ganglia showed interaction of the Schwann cells with axons, providing evidence of Schwann cell functionality. We conclude that hEPI-NCSCs are a biologically relevant source for generating large and highly pure populations of human Schwann cells. PMID:26251357

  8. The Tallahala Creek complex, Smith County, Mississippi: The crest is not always the best

    SciTech Connect

    Sticker, E.E.

    1994-12-31

    The Tallahala Creek complex, comprising both Tallahala Creek and East Tallahala Creek fields, is a salt-induced anticline transected by two down-to-the-north fault systems. Since 1967, the upper portion of the Jurassic Smackover Formation has yielded almost 15 million bbl of oil and 20 billion ft{sup 3} of gas, or 75 percent and 64 percent of the total oil and gas, respectively, produced from the fields. Contemporaneous sediment accumulation and structural growth have created various lithofacies in the upper Smackover, thereby significantly affecting reservoir heterogeneity. These lithofacies can be delineated by their structural position on the anticline. On the most downdip and downthrown portions of the structure, the upper Smackover consists of a series of gray, fine- to medium-grained sandstones separated by limestones. These sandstones generally exhibit both high porosity and permeability and have thus contributed more than 95 percent of the total Smackover production. Updip the upper Smackover becomes increasingly calcareous, finally grading into a sandy, in some places dolomitic, limestone on the crest and southern upthrown flank of the anticline. This limestone lithofacies has been noncommercial as a reservoir rock, as evidenced by the less than 7,000 bbl of oil cumulatively produced from the Smackover in two of the structurally highest wells, the Shell 2 E.M. Lane and the Shell 1 F. James. Structural and stratigraphic relationships discovered through field development of the Tallahala Creek complex have significantly altered the conventional idea that {open_quotes}the crest is always the best{close_quotes}.

  9. [Transplanted epidermal neural crest stem cell in a peripheral nerve gap].

    PubMed

    Zhang, Lu; Zhang, Jieyuan; Li, Bingcang; Liu, Zheng; Liu, Bin

    2014-04-01

    Neural crest stem cells originated from hair follicle (epidermal neural crest stem cell, EPI-NCSC) are easy to obtain and have potentials to differentiate into various tissues, which make them eminent seed cells for tissue engineering. EPI-NCSC is now used to repair nerve injury, especially, the spinal cord injury. To investigate their effects on repairing peripheral nerve injury, EPI-NCSC from a GFP-SD rat were primarily cultured on coated dishes and on a poly lactic acid coglycolic acid copolymer (PLGA) membrane. Methyl thiazolyl tetrazolium (MTT) assay showed that the initial adhesion rate of EPI-NCSC was 89.7% on PLGA membrane, and the relative growth rates were 89.3%, 87.6%, 85.6%, and 96.6% on the 1st, 3rd, 5th, 7th day respectively. Cell cycles and DNA ploidy analysis demonstrated that cell cycles and proliferation indexes of cultured EPI-NCSC had the same variation pattern on coated dishes and PLGA membrane. Then cultured EPI-NCSC were mixed with equal amount of extracellular matrix and injected into a PLGA conduit to connect a 10 mm surgery excision gap of rat sciatic nerve, Dulbecco's Modified Eagle's medium (DMEM) was used to substitute EPI-NCSC in the control group. After four weeks of transplantation, the defected sciatic nerve achieved a histological restoration, the sensory function of rat hind limb was partly recovered and the sciatic nerve index was also improved. The above results showed that a PLGA conduit filled with EPI-NCSC has a good repair effect on the peripheral nerve injury. PMID:25195250

  10. Genomic factors that shape craniofacial outcome and neural crest vulnerability in FASD

    PubMed Central

    Smith, Susan M.; Garic, Ana; Berres, Mark E.; Flentke, George R.

    2014-01-01

    Prenatal alcohol exposure (PAE) causes distinctive facial characteristics in some pregnancies and not others; genetic factors may contribute to this differential vulnerability. Ethanol disrupts multiple events of neural crest development, including induction, survival, migration, and differentiation. Animal models and genomic approaches have substantially advanced our understanding of the mechanisms underlying these facial changes. PAE during gastrulation produces craniofacial changes corresponding with human fetal alcohol syndrome. These result because PAE reduces prechordal plate extension and suppresses sonic hedgehog, leading to holoprosencephaly and malpositioned facial primordia. Haploinsufficiency in sonic hedgehog signaling increases vulnerability to facial deficits and may influence some PAE pregnancies. In contrast, PAE during early neurogenesis produces facial hypoplasia, preceded by neural crest reductions due to significant apoptosis. Factors mediating this apoptosis include intracellular calcium mobilization, elevated reactive oxygen species, and loss of trophic support from β-catenin/calcium, sonic hedgehog, and mTOR signaling. Genome-wide SNP analysis links PDGFRA with facial outcomes in human PAE. Multiple genomic-level comparisons of ethanol-sensitive and – resistant early embryos, in both mouse and chick, independently identify common candidate genes that may potentially modify craniofacial vulnerability, including ribosomal proteins, proteosome, RNA splicing, and focal adhesion. In summary, research using animal models with genome-level differences in ethanol vulnerability, as well as targeted loss-and gain-of-function mutants, has clarified the mechanisms mediating craniofacial change in PAE. The findings additionally suggest that craniofacial deficits may represent a gene–ethanol interaction for some affected individuals. Genetic-level changes may prime individuals toward greater sensitivity or resistance to ethanol’s neurotoxicity

  11. Identification of novel Hoxa1 downstream targets regulating hindbrain, neural crest and inner ear development

    PubMed Central

    Makki, Nadja; Capecchi, Mario R.

    2011-01-01

    Hoxgenes play a crucial role during embryonic patterning and organogenesis. Of the 39 Hox genes, Hoxa1 is the first to be expressed during embryogenesis and the only anterior Hox gene linked to a human syndrome. Hoxa1 is necessary for proper development of the brainstem, inner ear and heart in humans and mice; however, almost nothing is known about the molecular downstream targets through which it exerts its function. To gain insight into the transcriptional network regulated by this protein, we performed microarray analysis on tissue microdissected from the prospective rhombomere 3–5 region of Hoxa1 null and wild type embryos. Due to the very early and transient expression of this gene, dissections were performed on early somite stage embryos during an eight-hour time window of development. Our array yielded a list of around 300 genes differentially expressed between the two samples. Many of the identified genes play a role in a specific developmental or cellular process. Some of the validated targets regulate early neural crest induction and specification. Interestingly, three of these genes, Zic1, Hnf1b and Foxd3, were down-regulated in the posterior hindbrain, where cardiac neural crest cells arise, which pattern the outflow tract of the heart. Other targets are necessary for early inner ear development, e.g. Pax8 and Fgfr3 or are expressed in specific hindbrain neurons regulating respiration, e.g. Lhx5. These findings allow us to propose a model where Hoxa1 acts in a genetic cascade upstream of genes controlling specific aspects of embryonic development, thereby providing insight into possible mechanisms underlying the human HoxA1-syndrome. PMID:21784065

  12. Genomic factors that shape craniofacial outcome and neural crest vulnerability in FASD.

    PubMed

    Smith, Susan M; Garic, Ana; Berres, Mark E; Flentke, George R

    2014-01-01

    Prenatal alcohol exposure (PAE) causes distinctive facial characteristics in some pregnancies and not others; genetic factors may contribute to this differential vulnerability. Ethanol disrupts multiple events of neural crest development, including induction, survival, migration, and differentiation. Animal models and genomic approaches have substantially advanced our understanding of the mechanisms underlying these facial changes. PAE during gastrulation produces craniofacial changes corresponding with human fetal alcohol syndrome. These result because PAE reduces prechordal plate extension and suppresses sonic hedgehog, leading to holoprosencephaly and malpositioned facial primordia. Haploinsufficiency in sonic hedgehog signaling increases vulnerability to facial deficits and may influence some PAE pregnancies. In contrast, PAE during early neurogenesis produces facial hypoplasia, preceded by neural crest reductions due to significant apoptosis. Factors mediating this apoptosis include intracellular calcium mobilization, elevated reactive oxygen species, and loss of trophic support from β-catenin/calcium, sonic hedgehog, and mTOR signaling. Genome-wide SNP analysis links PDGFRA with facial outcomes in human PAE. Multiple genomic-level comparisons of ethanol-sensitive and - resistant early embryos, in both mouse and chick, independently identify common candidate genes that may potentially modify craniofacial vulnerability, including ribosomal proteins, proteosome, RNA splicing, and focal adhesion. In summary, research using animal models with genome-level differences in ethanol vulnerability, as well as targeted loss-and gain-of-function mutants, has clarified the mechanisms mediating craniofacial change in PAE. The findings additionally suggest that craniofacial deficits may represent a gene-ethanol interaction for some affected individuals. Genetic-level changes may prime individuals toward greater sensitivity or resistance to ethanol's neurotoxicity. PMID

  13. Postotic and preotic cranial neural crest cells differently contribute to thyroid development.

    PubMed

    Maeda, Kazuhiro; Asai, Rieko; Maruyama, Kazuaki; Kurihara, Yukiko; Nakanishi, Toshio; Kurihara, Hiroki; Miyagawa-Tomita, Sachiko

    2016-01-01

    Thyroid development and formation vary among species, but in most species the thyroid morphogenesis consists of five stages: specification, budding, descent, bilobation and folliculogenesis. The detailed mechanisms of these stages have not been fully clarified. During early development, the cranial neural crest (CNC) contributes to the thyroid gland. The removal of the postotic CNC (corresponding to rhombomeres 6, 7 and 8, also known as the cardiac neural crest) results in abnormalities of the cardiovascular system, thymus, parathyroid glands, and thyroid gland. To investigate the influence of the CNC on thyroid bilobation process, we divided the CNC into two regions, the postotic CNC and the preotic CNC (from the mesencephalon to rhombomere 5) regions and examined. We found that preotic CNC-ablated embryos had a unilateral thyroid lobe, and confirmed the presence of a single lobe or the absence of lobes in postotic CNC-ablated chick embryos. The thyroid anlage in each region-ablated embryos was of a normal size at the descent stage, but at a later stage, the thyroid in preotic CNC-ablated embryos was of a normal size, conflicting with a previous report in which the thyroid was reduced in size in the postotic CNC-ablated embryos. The postotic CNC cells differentiated into connective tissues of the thyroid in quail-to-chick chimeras. In contrast, the preotic CNC cells did not differentiate into connective tissues of the thyroid. We found that preotic CNC cells encompassed the thyroid anlage from the specification stage to the descent stage. Finally, we found that endothelin-1 and endothelin type A receptor-knockout mice and bosentan (endothelin receptor antagonist)-treated chick embryos showed bilobation anomalies that included single-lobe formation. Therefore, not only the postotic CNC, but also the preotic CNC plays an important role in thyroid morphogenesis. PMID:26506449

  14. Neurogenesis of Neural Crest Derived Periodontal Ligament Stem Cells by EGF and bFGF

    PubMed Central

    Fortino, Veronica R.; Chen, Ren-Shiang; Pelaez, Daniel; Cheung, Herman S.

    2013-01-01

    Neuroregenerative medicine is an ever-growing field in which regeneration of lost cells/tissues due to a neurodegenerative disease is the ultimate goal. With the scarcity of available replacement alternatives, stem cells provide an attractive source for regenerating neural tissue. While many stem cell sources exist, including: mesenchymal stem cells (MSCs), embryonic stem cells (ESCs), and induced pluripotent stem cells (iPSCs), the limited cellular potency, technical difficulties, and ethical considerations associated with these make finding alternate sources a desirable goal. Periodontal ligament stem cells (PDLSCs) derived from the neural crest were induced into neural-like cells using a combination of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF). Morphological changes were evident in our treated group, seen under both light microscopy and scanning electron microscopy (SEM). A statistically significant increase in the expression of neuron-specific β-tubulin III and the neural stem/progenitor cell marker nestin, along with positive immunohistochemical staining for glial fibrillary acidic protein (GFAP), demonstrated the success of our treatment in inducing both neuronal and glial phenotypes. Positive staining for synaptophysin demonstrated neural connections and electrophysiological recordings indicated that when subjected to whole cell patch clamping, our treated cells displayed inward currents conducted through voltage-gated sodium (Na+) channels. Taken together, our results indicate the success of our treatment in inducing PDLSCs to neural-like cells. The ease of sourcing and expansion, their embryologic neural crest origin, and the lack of ethical implications in their use make PDLSCs an attractive source for use in neuroregenerative medicine. PMID:24105823

  15. Nesting habitat relationships of sympatric Crested Caracaras, Red-tailed Hawks, and White-tailed Hawks in South Texas

    USGS Publications Warehouse

    Actkinson, M.A.; Kuvlesky, W.P., Jr.; Boal, C.W.; Brennan, L.A.; Hernandez, F.

    2007-01-01

    We quantified nesting-site habitats for sympatric White-tailed Hawks (Buteo albicaudatus) (n = 40), Red-tailed Hawks (B. jamaicensis) (n = 39), and Crested Caracaras (Caracara cheriway) (n = 24) in the Coastal Sand Plain of south Texas. White-tailed Hawks and Crested Caracara nest sites occurred in savannas, whereas Red-tailed Hawk nest sites occurred in woodlands on the edge of savannas. White-tailed Hawk nest sites were in shrubs and trees that were shorter (3.5 ?? 1.0 m) and had smaller canopy diameters (5.5 ?? 2.1 m) than those of Red-tailed Hawks (10.1 ?? 2.0 m, 13.7 ?? 5.8 m) and Crested Caracaras (5.6 ?? 1.7 m, 8.5 ?? 3.5 m). Red-tailed Hawk nest sites had higher woody densities (15.7 ?? 9.6 plants) and more woody cover (84 ?? 19%) than those of White-tailed Hawks (5.6 ?? 5.8 plants, 20 ?? 21%) and Crested Caracaras (9.9 ?? 6.7 plants, 55 ?? 34%). Crested Caracara nest sites were in dense, multi-branched shrubs composed of more living material (97 ?? 3%) than those of White-tailed (88 ?? 18%) and Red-tailed hawks (88 ?? 18%). Nest sites of White-tailed Hawks, Red-tailed Hawks, and Crested Caracaras were similar to random samples from the surrounding habitat indicating that preferred nesting habitat was available for each of these species at least within 60 m of active nest sites. Nest tree height, along with woody plant and native grass cover best discriminated nest sites among the three raptor species. There was no overlap at Red-tailed and White-tailed hawk nest sites in vegetation structure, while Crested Caracara nests were in habitat intermediate between the two other species. Partitioning of nesting habitat may be how these raptor species co-exist at the broader landscape scale of our study area in the Coastal Sand Plain of Texas.

  16. Time-lapse analysis reveals a series of events by which cranial neural crest cells reroute around physical barriers.

    PubMed

    Kulesa, Paul M; Lu, Carole C; Fraser, Scott E

    2005-01-01

    Segmentation is crucial to the development of the vertebrate body plan. Underlying segmentation in the head is further revealed when cranial neural crest cells emerge from even numbered rhombomeres in the hindbrain to form three stereotypical migratory streams that lead to the peripheral branchial arches. To test the role of intrinsic versus extrinsic cues in influencing an individual cell's trajectory, we implanted physical barriers in the chick mesoderm, distal to emerging neural crest cell stream fronts. We analyzed the spatio-temporal dynamics as individual neural crest cells encountered and responded to the barriers, using time-lapse confocal imaging. We find the majority of neural crest cells reach the branchial arch destinations following a repeatable series of events by which the cells overcome the barriers. Even though the lead cells become temporarily blocked by a barrier, cells that follow from behind find a novel pathway around a barrier and become de novo leaders of a new stream. Surprisingly, quantitative analyses of cell trajectories show that cells that encounter an r3 barrier migrate significantly faster but less directly than cells that encounter an r4 barrier, which migrate normally. Interestingly, we also find that cells temporarily blocked by the barrier migrate slightly faster and change direction more often. In addition, we show that cells can be forced to migrate into normally repulsive territory. These results suggest that cranial neural crest cell trajectories are not intrinsically determined, that cells can respond to minor alterations in the environment and re-target a peripheral destination, and that both intrinsic and extrinsic cues are important in patterning. PMID:16254414

  17. Experimental biomechanical study of the primary stability of different osteosynthesis systems for mandibular reconstruction with an iliac crest graft.

    PubMed

    Grohmann, I; Raith, S; Kesting, M; Rau, A; Mücke, T; Lethaus, B; Hölzle, F; Steiner, T

    2013-12-01

    We did biomechanical loading tests to compare the quantity and quality of interfragmentary movement in fractured human cadaver mandibles that had been reconstructed with iliac crest using 3 different osteosynthesis systems. Eighteen mandibles from human cadavers with a 4.5 cm paramedian L-type defect were reconstructed with bone from the iliac crest using 3 different osteosynthesis systems and continuously loaded on the "Mandibulator" test bench. Six mandibles each had the bones joined together using 2 monocortical non-locking plates, 2 monocortical locking plates, or a single bicortical locking plate/fracture gap. Macroscopic deformation, failure mechanisms, and movement of the fracture gap in all 3 dimensions were assessed and quantified over increasing loading by PONTOS(®) optical measurement systems. Final mechanisms of failure were excessive deformation of the plate, fracture of the mandibular fragments, and failure of the iliac crest graft. The plate became deformed mainly in the miniplate group. The iliac crest graft failed in all the specimens in which osteosynthesis was performed by a 6-hole TriLock(®) plate. Interfragmentary movement was minimised in the miniplate group. All three osteosynthesis systems provided sufficient stability for reconstruction when mechanically loaded up to 100 N. The miniplate allowed less movement in the gap and gave better stability than the two TriLock(®) plate systems. The superiority of the miniplate was significant when compared with the 4-hole TriLock(®) plate. The transplant failed mainly in the 6-hole TriLock(®) group, which suggests that the iliac crest graft works better with the miniplate as a more malleable osteosynthesis system. PMID:23958348

  18. Osteocyte lacunar properties and cortical microstructure in human iliac crest as a function of age and sex.

    PubMed

    Bach-Gansmo, Fiona Linnea; Brüel, Annemarie; Jensen, Michael Vinkel; Ebbesen, Ebbe Nils; Birkedal, Henrik; Thomsen, Jesper Skovhus

    2016-10-01

    Osteocytes are suggested to play a central role in bone remodeling. Evaluation of iliac crest biopsies is a standard procedure for evaluating bone conditions in the clinical setting. Despite the widespread use of such biopsies, little is known about the population of osteocytes in the iliac crest from normal individuals. Contradicting results have been reported on osteocyte lacunar properties in human bone. Hence, a solid understanding of the osteocyte population in healthy bone and the effect of age and sex is needed as good reference data are lacking. Furthermore, the role of cortical bone in bone quality has recently been suggested to be more important than previously realized. Therefore, the present study assesses osteocyte lacunar properties and cortical microstructure of the iliac crest as a function of age and sex. A total of 88 iliac crest bone samples from healthy individuals (46 women, aged 18.5-96.4years and 42 men, aged 22.6-94.6years) with an even age-distribution were examined using synchrotron radiation μCT and in house μCT, with >5×10(6) osteocyte lacunae measured and analyzed. The study revealed that osteocyte lacunar volumes were unaffected by both age and sex. Osteocyte lacunar density did not differ between women and men, and only showed a significant decrease with age when pooling data from both sexes. Cortical porosity and Haversian canal density increased while cortical thickness decreased with age, with cortical thinning dominating the age-related cortical bone loss. None of the cortical microstructural parameters showed any sex dependency. Only weak links between osteocyte lacunar properties and cortical microstructural properties in iliac crest bone were found. Interestingly, the Haversian canal diameters were significantly but weakly negatively correlated with osteocyte lacunar volumes. PMID:27397700

  19. New technique for feline carbon dioxide laser onychectomy by resection of the redundant epidermis of the ungual crest

    NASA Astrophysics Data System (ADS)

    Young, William P.

    2000-05-01

    A new technique for feline carbon dioxide laser onychectomy can further minimize postoperative pain and complications in any age animal. This procedure is accomplished by resection of the redundant epidermis over the ungual crest. Resection of the redundant epidermis allows complete dissection and removal of the claw from a strictly cranio-dorsal approach, thereby minimizing trauma to the surrounding tissues and post- operative complications. The laser setting is preferred at four to six watts continuous power. The epidermis of the ungual crest is resected in a circumferential manner at its most distal edge. This tissue is pushed proximally over the ungual crest. A second circumferential incision is made 3 mm proximal to the first incision. Deeper subcutaneous fascia is also pushed proximally over the ungual crest. An incision of the extensor tendon is made at its insertion on the ungual crest keeping the redundant epidermis proximal to this incision. The incision through the extensor tendon is continued deeper to the synovium of PII and PIII. Gentle traction in a palmar direction will disarticulate the joint space between PII and PIII. Incisions into the lateral and medial collateral ligaments from a cranio-dorsal origin in palmar direction further disarticulate the joint. Care must be exercised to preserve all epidermal tissue lying immediately adjacent to the collateral ligaments. Continual palmar traction will expose the base of PIII and the insertion of the flexor tendon. A dorsal incision is made into the flexor tendon in a palmar direction. Extreme palmar rotation of PIII will allow the dissection of the subcutaneous tissue of the pad from PIII. The redundant epidermal tissue will now cover the majority of the onychectomy site. No sutures or tissue adhesive are advised.

  20. Multiple nuclear and mitochondrial genes resolve the branching order of a rapid radiation of crested newts (Triturus arntzenii) (corrected).

    PubMed

    Espregueira Themudo, G; Wielstra, B; Arntzen, J W

    2009-08-01

    Newts of the genus Triturus are parapatrically distributed across Europe. Within this group, the crested newts (Triturus cristatus superspecies) radiated in a short temporal interval. Given the relatively short timespan in between branching events and to address the gene tree-species tree problem, we sequenced two mitochondrial and five nuclear genes from populations representing the distribution range of all the five crested newt species. We built gene trees using non-hierarchical Bayesian phylogenetics and phylogenetic networks, and a species tree with a recently developed method, which uses a hierarchical Bayesian approach. While the single gene trees did not provide resolution, the hierarchical Bayesian method yielded an almost fully resolved species tree, even though branching events followed one another closely. Results show a previously undetected basal dichotomy between T. karelinii and the other four species and a deep differentiation of T. karelinii in two lineages, here raised to full species status. PMID:19348957

  1. Levee crest elevation profiles derived from airborne lidar-based high resolution digital elevation models in south Louisiana

    USGS Publications Warehouse

    Palaseanu-Lovejoy, Monica; Thatcher, Cindy A.; Barras, John A.

    2014-01-01

    This study explores the feasibility of using airborne lidar surveys to derive high-resolution digital elevation models (DEMs) and develop an automated procedure to extract levee longitudinal elevation profiles for both federal levees in Atchafalaya Basin and local levees in Lafourche Parish. Generally, the use of traditional manual surveying methods to map levees is a costly and time consuming process that typically produces cross-levee profiles every few hundred meters, at best. The purpose of our paper is to describe and test methods for extracting levee crest elevations in an efficient, comprehensive manner using high resolution lidar generated DEMs. In addition, the vertical uncertainty in the elevation data and its effect on the resultant estimate of levee crest heights is addressed in an assessment of whether the federal levees in our study meet the USACE minimum height design criteria.

  2. Cadherin Switch during EMT in Neural Crest Cells Leads to Contact Inhibition of Locomotion via Repolarization of Forces.

    PubMed

    Scarpa, Elena; Szabó, András; Bibonne, Anne; Theveneau, Eric; Parsons, Maddy; Mayor, Roberto

    2015-08-24

    Contact inhibition of locomotion (CIL) is the process through which cells move away from each other after cell-cell contact, and it contributes to malignant invasion and developmental migration. Various cell types exhibit CIL, whereas others remain in contact after collision and may form stable junctions. To investigate what determines this differential behavior, we study neural crest cells, a migratory stem cell population whose invasiveness has been likened to cancer metastasis. By comparing pre-migratory and migratory neural crest cells, we show that the switch from E- to N-cadherin during EMT is essential for acquisition of CIL behavior. Loss of E-cadherin leads to repolarization of protrusions, via p120 and Rac1, resulting in a redistribution of forces from intercellular tension to cell-matrix adhesions, which break down the cadherin junction. These data provide insight into the balance of physical forces that contributes to CIL in cells in vivo. PMID:26235046

  3. A comparative analysis of double-crested cormorant diets from stomachs and pellets from two Lake Ontario colonies

    USGS Publications Warehouse

    Johnson, James H.; Ross, Robert M.; McCullough, Russell D.; Mathers, Alastair

    2010-01-01

    Double-crested cormorant (Phalacrocorax auritus) diets were compared with evidence from the stomachs of shot birds and from regurgitated pellets at High Bluff Island and Little Galloo Island, Lake Ontario. The highest similarity in diets determined by stomach and pellet analyses occurred when both samples were collected on the same day. Diet overlap dropped substantially between the two methods when collection periods were seven to ten days apart, which suggested differences in prey availability between the two periods. Since the average number of fish recovered in pellets was significantly higher than that in stomachs, use of pellets to determine fish consumption of double-crested cormorants may be more valid than stomach analysis because pellet content represent an integrated sampling of food consumed over approximately 24 hours.

  4. Phosphorylation of Sox9 is required for neural crest delamination and is regulated downstream of BMP and canonical Wnt signaling.

    PubMed

    Liu, Jessica A J; Wu, Ming-Hoi; Yan, Carol H; Chau, Bolton K H; So, Henry; Ng, Alvis; Chan, Alan; Cheah, Kathryn S E; Briscoe, James; Cheung, Martin

    2013-02-19

    Coordination of neural crest cell (NCC) induction and delamination is orchestrated by several transcription factors. Among these, Sry-related HMG box-9 (Sox9) and Snail2 have been implicated in both the induction of NCC identity and, together with phoshorylation, NCC delamination. How phosphorylation effects this function has not been clear. Here we show, in the developing chick neural tube, that phosphorylation of Sox9 on S64 and S181 facilitates its SUMOylation, and the phosphorylated forms of Sox9 are essential for trunk neural crest delamination. Both phosphorylation and to a lesser extent SUMOylation, of Sox9 are required to cooperate with Snail2 to promote delamination. Moreover, bone morphogenetic protein and canonical Wnt signaling induce phosphorylation of Sox9, thereby connecting extracellular signals with the delamination of NCCs. Together the data suggest a model in which extracellular signals initiate phosphorylation of Sox9 and its cooperation with Snail2 to induce NCC delamination. PMID:23382206

  5. Cadherin Switch during EMT in Neural Crest Cells Leads to Contact Inhibition of Locomotion via Repolarization of Forces

    PubMed Central

    Scarpa, Elena; Szabó, András; Bibonne, Anne; Theveneau, Eric; Parsons, Maddy; Mayor, Roberto

    2015-01-01

    Summary Contact inhibition of locomotion (CIL) is the process through which cells move away from each other after cell-cell contact, and it contributes to malignant invasion and developmental migration. Various cell types exhibit CIL, whereas others remain in contact after collision and may form stable junctions. To investigate what determines this differential behavior, we study neural crest cells, a migratory stem cell population whose invasiveness has been likened to cancer metastasis. By comparing pre-migratory and migratory neural crest cells, we show that the switch from E- to N-cadherin during EMT is essential for acquisition of CIL behavior. Loss of E-cadherin leads to repolarization of protrusions, via p120 and Rac1, resulting in a redistribution of forces from intercellular tension to cell-matrix adhesions, which break down the cadherin junction. These data provide insight into the balance of physical forces that contributes to CIL in cells in vivo. PMID:26235046

  6. Winter and summer home ranges and core use areas of double-crested cormorants captured near aquaculture facilities in the southeastern United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Migration patterns of Double-crested Cormorants (Phalacrocorax auritus) wintering in the southeastern United States are poorly understood. Movement data was analyzed from 28 cormorants captured in Alabama, Arkansas, Louisiana, and Mississippi and equipped with satellite transmitters. Four (3 immatur...

  7. Structure and Polymorphism of the Major Histocompatibility Complex Class II Region in the Japanese Crested Ibis, Nipponia nippon

    PubMed Central

    Taniguchi, Yukio; Matsumoto, Keisuke; Matsuda, Hirokazu; Yamada, Takahisa; Sugiyama, Toshie; Homma, Kosuke; Kaneko, Yoshinori; Yamagishi, Satoshi; Iwaisaki, Hiroaki

    2014-01-01

    The major histocompatibility complex (MHC) is a highly polymorphic genomic region that plays a central role in the immune system. Despite its functional consistency, the genomic structure of the MHC differs substantially among organisms. In birds, the MHC-B structures of Galliformes, including chickens, have been well characterized, but information about other avian MHCs remains sparse. The Japanese Crested Ibis (Nipponia nippon, Pelecaniformes) is an internationally conserved, critically threatened species. The current Japanese population of N. nippon originates from only five founders; thus, understanding the genetic diversity among these founders is critical for effective population management. Because of its high polymorphism and importance for disease resistance and other functions, the MHC has been an important focus in the conservation of endangered species. Here, we report the structure and polymorphism of the Japanese Crested Ibis MHC class II region. Screening of genomic libraries allowed the construction of three contigs representing different haplotypes of MHC class II regions. Characterization of genomic clones revealed that the MHC class II genomic structure of N. nippon was largely different from that of chicken. A pair of MHC-IIA and -IIB genes was arranged head-to-head between the COL11A2 and BRD2 genes. Gene order in N. nippon was more similar to that in humans than to that in chicken. The three haplotypes contained one to three copies of MHC-IIA/IIB gene pairs. Genotyping of the MHC class II region detected only three haplotypes among the five founders, suggesting that the genetic diversity of the current Japanese Crested Ibis population is extremely low. The structure of the MHC class II region presented here provides valuable insight for future studies on the evolution of the avian MHC and for conservation of the Japanese Crested Ibis. PMID:25247679

  8. Phenothiourea sensitizes zebrafish cranial neural crest and extraocular muscle development to changes in retinoic acid and IGF signaling.

    PubMed

    Bohnsack, Brenda L; Gallina, Donika; Kahana, Alon

    2011-01-01

    1-Phenyl 2-thiourea (PTU) is a tyrosinase inhibitor commonly used to block pigmentation and aid visualization of zebrafish development. At the standard concentration of 0.003% (200 µM), PTU inhibits melanogenesis and reportedly has minimal other effects on zebrafish embryogenesis. We found that 0.003% PTU altered retinoic acid and insulin-like growth factor (IGF) regulation of neural crest and mesodermal components of craniofacial development. Reduction of retinoic acid synthesis by the pan-aldehyde dehydrogenase inhibitor diethylbenzaldehyde, only when combined with 0.003% PTU, resulted in extraocular muscle disorganization. PTU also decreased retinoic acid-induced teratogenic effects on pharyngeal arch and jaw cartilage despite morphologically normal appearing PTU-treated controls. Furthermore, 0.003% PTU in combination with inhibition of IGF signaling through either morpholino knockdown or pharmacologic inhibition of tyrosine kinase receptor phosphorylation, disrupted jaw development and extraocular muscle organization. PTU in and of itself inhibited neural crest development at higher concentrations (0.03%) and had the greatest inhibitory effect when added prior to 22 hours post fertilization (hpf). Addition of 0.003% PTU between 4 and 20 hpf decreased thyroxine (T4) in thyroid follicles in the nasopharynx of 96 hpf embryos. Treatment with exogenous triiodothyronine (T3) and T4 improved, but did not completely rescue, PTU-induced neural crest defects. Thus, PTU should be used with caution when studying zebrafish embryogenesis as it alters the threshold of different signaling pathways important during craniofacial development. The effects of PTU on neural crest development are partially caused by thyroid hormone signaling. PMID:21886774

  9. An FGF3-BMP Signaling Axis Regulates Caudal Neural Tube Closure, Neural Crest Specification and Anterior-Posterior Axis Extension

    PubMed Central

    Anderson, Matthew J.; Schimmang, Thomas; Lewandoski, Mark

    2016-01-01

    During vertebrate axis extension, adjacent tissue layers undergo profound morphological changes: within the neuroepithelium, neural tube closure and neural crest formation are occurring, while within the paraxial mesoderm somites are segmenting from the presomitic mesoderm (PSM). Little is known about the signals between these tissues that regulate their coordinated morphogenesis. Here, we analyze the posterior axis truncation of mouse Fgf3 null homozygotes and demonstrate that the earliest role of PSM-derived FGF3 is to regulate BMP signals in the adjacent neuroepithelium. FGF3 loss causes elevated BMP signals leading to increased neuroepithelium proliferation, delay in neural tube closure and premature neural crest specification. We demonstrate that elevated BMP4 depletes PSM progenitors in vitro, phenocopying the Fgf3 mutant, suggesting that excessive BMP signals cause the Fgf3 axis defect. To test this in vivo we increased BMP signaling in Fgf3 mutants by removing one copy of Noggin, which encodes a BMP antagonist. In such mutants, all parameters of the Fgf3 phenotype were exacerbated: neural tube closure delay, premature neural crest specification, and premature axis termination. Conversely, genetically decreasing BMP signaling in Fgf3 mutants, via loss of BMP receptor activity, alleviates morphological defects. Aberrant apoptosis is observed in the Fgf3 mutant tailbud. However, we demonstrate that cell death does not cause the Fgf3 phenotype: blocking apoptosis via deletion of pro-apoptotic genes surprisingly increases all Fgf3 defects including causing spina bifida. We demonstrate that this counterintuitive consequence of blocking apoptosis is caused by the increased survival of BMP-producing cells in the neuroepithelium. Thus, we show that FGF3 in the caudal vertebrate embryo regulates BMP signaling in the neuroepithelium, which in turn regulates neural tube closure, neural crest specification and axis termination. Uncovering this FGF3-BMP signaling axis is

  10. Reprogramming metastatic melanoma cells to assume a neural crest cell-like phenotype in an embryonic microenvironment

    PubMed Central

    Kulesa, Paul M.; Kasemeier-Kulesa, Jennifer C.; Teddy, Jessica M.; Margaryan, Naira V.; Seftor, Elisabeth A.; Seftor, Richard E. B.; Hendrix, Mary J. C.

    2006-01-01

    Human metastatic melanoma cells express a dedifferentiated, plastic phenotype, which may serve as a selective advantage, because melanoma cells invade various microenvironments. Over the last three decades, there has been an increased focus on the role of the tumor microenvironment in cancer progression, with the goal of reversing the metastatic phenotype. Here, using an embryonic chick model, we explore the possibility of reverting the metastatic melanoma phenotype to its cell type of origin, the neural-crest-derived melanocyte. GFP-labeled adult human metastatic melanoma cells were transplanted in ovo adjacent to host chick premigratory neural crest cells and analyzed 48 and 96 h after egg reincubation. Interestingly, the transplanted melanoma cells do not form tumors. Instead, we find that transplanted melanoma cells invade surrounding chick tissues in a programmed manner, distributing along host neural-crest-cell migratory pathways. The invading melanoma cells display neural-crest-cell-like morphologies and populate host peripheral structures, including the branchial arches, dorsal root and sympathetic ganglia. Analysis of a melanocyte-specific phenotype marker (MART-1) and a neuronal marker (Tuj1) revealed a subpopulation of melanoma cells that invade the chick periphery and express MART-1 and Tuj1. Our results demonstrate the ability of adult human metastatic melanoma cells to respond to chick embryonic environmental cues, a subset of which may undergo a reprogramming of their metastatic phenotype. This model has the potential to provide insights into the regulation of tumor cell plasticity by an embryonic milieu, which may hold significant therapeutic promise. PMID:16505384

  11. Skeletal site-specific characterization of orofacial and iliac crest human bone marrow stromal cells in same individuals.

    PubMed

    Akintoye, Sunday O; Lam, Thanh; Shi, Songtao; Brahim, Jaime; Collins, Michael T; Robey, Pamela G

    2006-06-01

    Autologous grafts from axial and appendicular bones commonly used to repair orofacial bone defects often result in unfavorable outcome. This clinical observation, along with the fact that many bone abnormalities are limited to craniofacial bones, suggests that there are significant differences in bone metabolism in orofacial, axial and appendicular bones. It is plausible that these differences are dictated by site-specificity of embryological progenitor cells and osteogenic properties of resident multipotent human bone marrow stromal cells (hBMSCs). This study investigated skeletal site-specific phenotypic and functional differences between orofacial (maxilla and mandible) and axial (iliac crest) hBMSCs in vitro and in vivo. Primary cultures of maxilla, mandible and iliac crest hBMSCs were established with and without osteogenic inducers. Site-specific characterization included colony forming efficiency, cell proliferation, life span before senescence, relative presence of surface markers, adipogenesis, osteogenesis and transplantation in immunocompromised mice to compare bone regenerative capacity. Compared with iliac crest cells, orofacial hBMSCs (OF-MSCs) proliferated more rapidly with delayed senescence, expressed higher levels of alkaline phosphatase and demonstrated more calcium accumulation in vitro. Cells isolated from the three skeletal sites were variably positive for STRO 1, a marker of hBMSCs. OF-MSCs formed more bone in vivo, while iliac crest hBMSCs formed more compacted bone that included hematopoietic tissue and were more responsive in vitro and in vivo to osteogenic and adipogenic inductions. These data demonstrate that hBMSCs from the same individuals differ in vitro and in vivo in a skeletal site-specific fashion and identified orofacial marrow stromal cells as unique cell populations. Further understanding of site-specific properties of hBMSCs and their impact on site-specific bone diseases and regeneration are needed. PMID:16403496

  12. An FGF3-BMP Signaling Axis Regulates Caudal Neural Tube Closure, Neural Crest Specification and Anterior-Posterior Axis Extension.

    PubMed

    Anderson, Matthew J; Schimmang, Thomas; Lewandoski, Mark

    2016-05-01

    During vertebrate axis extension, adjacent tissue layers undergo profound morphological changes: within the neuroepithelium, neural tube closure and neural crest formation are occurring, while within the paraxial mesoderm somites are segmenting from the presomitic mesoderm (PSM). Little is known about the signals between these tissues that regulate their coordinated morphogenesis. Here, we analyze the posterior axis truncation of mouse Fgf3 null homozygotes and demonstrate that the earliest role of PSM-derived FGF3 is to regulate BMP signals in the adjacent neuroepithelium. FGF3 loss causes elevated BMP signals leading to increased neuroepithelium proliferation, delay in neural tube closure and premature neural crest specification. We demonstrate that elevated BMP4 depletes PSM progenitors in vitro, phenocopying the Fgf3 mutant, suggesting that excessive BMP signals cause the Fgf3 axis defect. To test this in vivo we increased BMP signaling in Fgf3 mutants by removing one copy of Noggin, which encodes a BMP antagonist. In such mutants, all parameters of the Fgf3 phenotype were exacerbated: neural tube closure delay, premature neural crest specification, and premature axis termination. Conversely, genetically decreasing BMP signaling in Fgf3 mutants, via loss of BMP receptor activity, alleviates morphological defects. Aberrant apoptosis is observed in the Fgf3 mutant tailbud. However, we demonstrate that cell death does not cause the Fgf3 phenotype: blocking apoptosis via deletion of pro-apoptotic genes surprisingly increases all Fgf3 defects including causing spina bifida. We demonstrate that this counterintuitive consequence of blocking apoptosis is caused by the increased survival of BMP-producing cells in the neuroepithelium. Thus, we show that FGF3 in the caudal vertebrate embryo regulates BMP signaling in the neuroepithelium, which in turn regulates neural tube closure, neural crest specification and axis termination. Uncovering this FGF3-BMP signaling axis is

  13. Fast tool for evaluation of iliac crest tissue elastic properties using the reduced-basis methods.

    PubMed

    Lee, Taeyong; Garlapati, Revanth Reddy; Lam, Kathy; Lee, Peter Vee Sin; Chung, Yoon-Sok; Choi, Jae Bong; Vincent, Tan Beng Chye; Das De, Shamal

    2010-12-01

    Computationally expensive finite element (FE) methods are generally used for indirect evaluation of tissue mechanical properties of trabecular specimens, which is vital for fracture risk prediction in the elderly. This work presents the application of reduced-basis (RB) methods for rapid evaluation of simulation results. Three cylindrical transiliac crest specimens (diameter: 7.5 mm, length: 10-12 mm) were obtained from healthy subjects (20 year-old, 22 year-old, and 24 year-old females) and scanned using microcomputed tomography imaging. Cubic samples of dimensions 5×5×5 mm(3) were extracted from the core of the cylindrical specimens for FE analysis. Subsequently, a FE solution library (test space) was constructed for each of the specimens by varying the material property parameters: tissue elastic modulus and Poisson's ratio, to develop RB algorithms. The computational speed gain obtained by the RB methods and their accuracy relative to the FE analysis were evaluated. Speed gains greater than 4000 times, were obtained for all three specimens for a loss in accuracy of less than 1% in the maxima of von-Mises stress with respect to the FE-based value. The computational time decreased from more than 6 h to less than 18 s. RB algorithms can be successfully utilized for real-time reliable evaluation of trabecular bone elastic properties. PMID:21142323

  14. An archaic crested plesiosaur in opal from the Lower Cretaceous high-latitude deposits of Australia.

    PubMed

    Kear, Benjamin P; Schroeder, Natalie I; Lee, Michael S Y

    2006-12-22

    Umoonasaurus demoscyllus gen. et sp. nov. is a new small-bodied (approx. 2.5m) pliosauroid plesiosaur from the Lower Cretaceous (Aptian-Albian) of southern Australia. It is represented by several partial skeletons (one with a near complete skull is the most complete opalized vertebrate fossil yet known), and is unique in having large crests on the skull midline and above the orbits. Umoonasaurus is surprisingly archaic despite its relatively late age (approx. 115 Myr ago)--being simultaneously the most basal (primitive) and last surviving rhomaleosaurid. Notably, it lacks the 'pliosauromorph' features (large head, short neck, gigantism) typically characterizing many more derived Jurassic rhomaleosaurids; thus, reinforcing the suspected convergent evolution of the 'pliosauromorph' hypercarnivore body plan. Umoonasaurus inhabited an Early Cretaceous high-latitude (approx. 70 degrees S) inland seaway subject to seasonally near-freezing climatic conditions. This extreme environment supported a diverse range of plesiosaur taxa, suggesting that these marine reptiles might have possessed adaptations (e.g. heightened metabolic levels) to cope with cold-water temperatures. Indeed, survival of ancient endemic lineages such as Umoonasaurus is a common phenomenon in Australian Cretaceous vertebrate assemblages and might have been facilitated by isolation in low-temperature high-latitude regions. PMID:17148303

  15. Environmental contaminants, human disturbance and nesting of double-crested cormorants in northwestern Washington

    USGS Publications Warehouse

    Henny, C.J.; Blus, L.J.; Thompson, S.P.; Wilson, U.W.

    1989-01-01

    Double-crested Cormorants (Phalacrocorax auritus) in extreme northwestern Washington produced few young (0.27/occupied nest) in 1984; the clutch size was generally small and eggs, if laid at all, were laid later than usual. Residues (geometric means, wet weight) of DDE (0.58 and 0.59 ppm) in eggs from Colville Island and Protection Island were lower than from other locations in the Pacific Northwest, while PCBs (2.19 and 1.37 ppm) were similar to those at most locations. Both contaminants in 1984 were below levels associated with reproductive problems. Eggs also contained concentrations of mercury (0.26 and 0.27 ppm) and selenium (0.31 and 0.28 ppm) below levels associated with reproductive problems. The distribution of nesting colonies in the study area changed dramatically since 1984. The cormorants were most likely responding to increased human disturbance in the San Juan Islands, coupled to additional protection and reduced human activity on Protection and Smith Islands. This presumably led to the abandonment of all nesting islands in the San Juans. The nesting population in the study area in 1988 (all on Protection and Smith Islands) was the highest recorded.

  16. Polychlorinated biphenyl residues and egg mortality in double-crested cormorants from the Great Lakes

    USGS Publications Warehouse

    Tillitt, D.E.; Ankley, G.T.; Giesy, J.P.; Ludwig, J.P.; Kurita-Matsuba, H.; Weseloh, D.V.; Ross, P.S.; Bishop, C.A.; Sileo, L.; Stromborg, K.L.; Larson, J.; Kubiak, T.J.

    1992-01-01

    We evaluated the overall potency of polychlorinated biphenyl (PCB)-containing extracts from double-crested cormorant (Phalacrocorax auritis) eggs with an in vitro bioassay system, the H4IIE rat hepatoma cell bioassay. Results from the H4IIE bioassay were strongly correlated with the hatching success of eggs in the colonies, whereas conventional methods of PCB analysis correlated poorly with hatching success of eggs from the same colonies. These observations suggest that even though concentrations of total PCB residues have declined in almost all compartments of the environment, their effects are still being observed. The significance of this observation is that the adverse symptoms presently observed in certain Great Lakes fish-eating waterbird populations do not appear to be caused by some as yet unidentified industrial chemical or chemicals and seem not to be the result of pesticides, but rather to the dioxin-like activity of PCBs. Evidence is presented to suggest that the relative enrichment of the potency of PCBs in the environment may play a role in the persistence of the observed adverse symptoms.

  17. Regulators of gene expression in Enteric Neural Crest Cells are putative Hirschsprung disease genes.

    PubMed

    Schriemer, Duco; Sribudiani, Yunia; IJpma, Arne; Natarajan, Dipa; MacKenzie, Katherine C; Metzger, Marco; Binder, Ellen; Burns, Alan J; Thapar, Nikhil; Hofstra, Robert M W; Eggen, Bart J L

    2016-08-01

    The enteric nervous system (ENS) is required for peristalsis of the gut and is derived from Enteric Neural Crest Cells (ENCCs). During ENS development, the RET receptor tyrosine kinase plays a critical role in the proliferation and survival of ENCCs, their migration along the developing gut, and differentiation into enteric neurons. Mutations in RET and its ligand GDNF cause Hirschsprung disease (HSCR), a complex genetic disorder in which ENCCs fail to colonize variable lengths of the distal bowel. To identify key regulators of ENCCs and the pathways underlying RET signaling, gene expression profiles of untreated and GDNF-treated ENCCs from E14.5 mouse embryos were generated. ENCCs express genes that are involved in both early and late neuronal development, whereas GDNF treatment induced neuronal maturation. Predicted regulators of gene expression in ENCCs include the known HSCR genes Ret and Sox10, as well as Bdnf, App and Mapk10. The regulatory overlap and functional interactions between these genes were used to construct a regulatory network that is underlying ENS development and connects to known HSCR genes. In addition, the adenosine receptor A2a (Adora2a) and neuropeptide Y receptor Y2 (Npy2r) were identified as possible regulators of terminal neuronal differentiation in GDNF-treated ENCCs. The human orthologue of Npy2r maps to the HSCR susceptibility locus 4q31.3-q32.3, suggesting a role for NPY2R both in ENS development and in HSCR. PMID:27266404

  18. The EJC component Magoh regulates proliferation and expansion of neural crest-derived melanocytes.

    PubMed

    Silver, Debra L; Leeds, Karen E; Hwang, Hun-Way; Miller, Emily E; Pavan, William J

    2013-03-15

    Melanoblasts are a population of neural crest-derived cells that generate the pigment-producing cells of our body. Defective melanoblast development and function underlies many disorders including Waardenburg syndrome and melanoma. Understanding the genetic regulation of melanoblast development will help elucidate the etiology of these and other neurocristopathies. Here we demonstrate that Magoh, a component of the exon junction complex, is required for normal melanoblast development. Magoh haploinsufficient mice are hypopigmented and exhibit robust genetic interactions with the transcription factor, Sox10. These phenotypes are caused by a marked reduction in melanoblast number beginning at mid-embryogenesis. Strikingly, while Magoh haploinsufficiency severely reduces epidermal melanoblasts, it does not significantly affect the number of dermal melanoblasts. These data indicate Magoh impacts melanoblast development by disproportionately affecting expansion of epidermal melanoblast populations. We probed the cellular basis for melanoblast reduction and discovered that Magoh mutant melanoblasts do not undergo increased apoptosis, but instead are arrested in mitosis. Mitotic arrest is evident in both Magoh haploinsufficient embryos and in Magoh siRNA treated melanoma cell lines. Together our findings indicate that Magoh-regulated proliferation of melanoblasts in the dermis may be critical for production of epidermally-bound melanoblasts. Our results point to a central role for Magoh in melanocyte development. PMID:23333945

  19. Daily foraging patterns of adult Double-crested Cormorants during the breeding season

    USGS Publications Warehouse

    Coleman, J.T.H.; Richmond, M.E.

    2007-01-01

    We recorded the daily presence of Double-crested Cormorants (Phalacrocorax auritus) at the nesting island on Oneida Lake, New York, by monitoring the activities of 15 radio-tagged adults from July through September, 2000, using an automated data-logging receiver. A total of 24,464 acceptable detections was obtained for adult cormorants actively attempting to nest on the lake. Tagged cormorants had a bimodal dally activity pattern during the first month, with the fewest birds detected on the island at 09.00 h and 15.00 h Eastern daylight time. The pattern of activity appeared to change slightly in the second month of the study, representative of a post-breeding period for the colony, with a shift from a less synchronous pattern of departures to a greater focus on morning activity also centered around 09.30 h. These results correspond with daily observations of Great Cormorant (P. carbo) foraging activities reported for colonies in Africa and Poland. The data also support the possibility of nocturnal foraging activity, not previously reported for this species on their summer breeding grounds. No correlation was found between total number of daily detections and climatalogical factors or events.

  20. Yap and Taz play a crucial role in neural crest-derived craniofacial development.

    PubMed

    Wang, Jun; Xiao, Yang; Hsu, Chih-Wei; Martinez-Traverso, Idaliz M; Zhang, Min; Bai, Yan; Ishii, Mamoru; Maxson, Robert E; Olson, Eric N; Dickinson, Mary E; Wythe, Joshua D; Martin, James F

    2016-02-01

    The role of the Hippo signaling pathway in cranial neural crest (CNC) development is poorly understood. We used the Wnt1(Cre) and Wnt1(Cre2SOR) drivers to conditionally ablate both Yap and Taz in the CNC of mice. When using either Cre driver, Yap and Taz deficiency in the CNC resulted in enlarged, hemorrhaging branchial arch blood vessels and hydrocephalus. However, Wnt1(Cre2SOR) mutants had an open cranial neural tube phenotype that was not evident in Wnt1(Cre) mutants. In O9-1 CNC cells, the loss of Yap impaired smooth muscle cell differentiation. RNA-sequencing data indicated that Yap and Taz regulate genes encoding Fox transcription factors, specifically Foxc1. Proliferation was reduced in the branchial arch mesenchyme of Yap and Taz CNC conditional knockout (CKO) embryos. Moreover, Yap and Taz CKO embryos had cerebellar aplasia similar to Dandy-Walker spectrum malformations observed in human patients and mouse embryos with mutations in Foxc1. In embryos and O9-1 cells deficient for Yap and Taz, Foxc1 expression was significantly reduced. Analysis of Foxc1 regulatory regions revealed a conserved recognition element for the Yap and Taz DNA binding co-factor Tead. ChIP-PCR experiments supported the conclusion that Foxc1 is directly regulated by the Yap-Tead complex. Our findings uncover important roles for Yap and Taz in CNC diversification and development. PMID:26718006

  1. Myxofibroma of the maxilla. Reconstruction with iliac crest graft and dental implants after tumor resection.

    PubMed

    Infante-Cossío, Pedro; Martínez-de-Fuentes, Rafael; García-Perla-García, Alberto; Jiménez-Castellanos, Emilio; Gómez-Izquierdo, Lourdes

    2011-07-01

    Odontogenic fibromyxomas are benign odontogenic tumors of mesenchymal origin of rare presentation in the oral cavity, which exhibit locally aggressive behavior and are prone to local recurrence. The controversy has mainly been on therapeutic management with recommendations varying, depending on the clinical cases, from simple curettage of lesion to segmental bone resection. We present a case report describing the reconstruction of an osseous defect in the maxilla and the restoration with dental implants in a 32 year old female patient after radical surgical excision due to an odontogenic fibromyxoma with locally aggressive behavior. The primary reconstruction of maxillary discontinuity defect was carried out by an immediate non-vascularized cortico-cancellous iliac crest graft. Using a computer-guided system for the implant treatment-planning, three dental implants were secondary placed in the bone graft by means of flapless implant surgery. The patient was subsequently restored with an implant-supported fixed prosthesis that has remained in continuous function for a period of three years. The surgical, reconstructive and restorative treatment sequence and techniques are discussed. PMID:20526263

  2. Molecular detection of bacteria in the families Rickettsiaceae and Anaplasmataceae in northern crested caracaras (Caracara cheriway)

    USGS Publications Warehouse

    Erwin, John A.; Fitak, Robert R.; Dwyer, James F.; Morrison, Joan L.; Culver, Melanie

    2016-01-01

    Bacterial pathogens of the families Anaplasmataceae and Rickettsiaceae are often spread to humans or other animals from bites from infected arthropod hosts. Recently, an increasing number of studies have implicated migratory birds in the circulation of these pathogens through the spread of arthropod vectors. However, few studies have examined the potential for resident bird populations to serve as reservoirs for these zoonoses. In this study, we used nested PCRs of the GroESL and 17 kDa genes to screen for Anaplasmataceae and Rickettsiaceae, respectively, in a resident population of the northern crested caracara (Caracara cheriway) from Florida (n = 55). Additionally, a small number (n = 6) of captive individuals from Texas were included. We identified one individual (1.64%) positive for Rickettsia felis and one (1.64%) positive for Ehrlichia chaffeensis; both these individuals were from Florida. Presence of these pathogens demonstrates that these birds are potential hosts; however, the low prevalence of infections suggests that these populations likely do not function as an ecological reservoir.

  3. A zebrafish melanoma model reveals emergence of neural crest identity during melanoma initiation

    PubMed Central

    Kaufman, Charles K.; Mosimann, Christian; Fan, Zi Peng; Yang, Song; Thomas, Andrew; Ablain, Julien; Tan, Justin L.; Fogley, Rachel D.; van Rooijen, Ellen; Hagedorn, Elliott; Ciarlo, Christie; White, Richard; Matos, Dominick; Puller, Ann-Christin; Santoriello, Cristina; Liao, Eric; Young, Richard A.; Zon, Leonard I.

    2016-01-01

    The “cancerized field” concept posits that cells in a given tissue share an oncogenic mutation or insult and are thus cancer-prone, yet only discreet clones within the field initiate tumors. Nearly all benign nevi carry oncogenic BRAFV600E mutations, but they only rarely become melanoma. The zebrafish crestin gene is expressed embryonically in neural crest progenitors (NCP’s) and is specifically re-expressed in melanoma. We show by live imaging of transgenic zebrafish crestin reporters that, within a cancerized field (BRAFV600E-mutant; p53-deficient), a single melanocyte reactivates the NCP state, and this establishes that a fate change occurs at melanoma initiation in this model. We show the crestin element is regulated by NCP transcription factors, including sox10. Forced sox10 overexpression in melanocytes accelerated melanoma formation, consistent with activation of a NCP gene signature and super-enhancers leading to melanoma. Our work highlights the importance of NCP state reemergence as a key event in melanoma initiation. PMID:26823433

  4. Are neural crest stem cells the missing link between hematopoietic and neurogenic niches?

    PubMed Central

    Coste, Cécile; Neirinckx, Virginie; Gothot, André; Wislet, Sabine; Rogister, Bernard

    2015-01-01

    Hematopoietic niches are defined as cellular and molecular microenvironments that regulate hematopoietic stem cell (HSC) function together with stem cell autonomous mechanisms. Many different cell types have been characterized as contributors to the formation of HSC niches, such as osteoblasts, endothelial cells, Schwann cells, and mesenchymal progenitors. These mesenchymal progenitors have themselves been classified as CXC chemokine ligand (CXCL) 12-abundant reticular (CAR) cells, stem cell factor expressing cells, or nestin-positive mesenchymal stem cells (MSCs), which have been recently identified as neural crest-derived cells (NCSCs). Together, these cells are spatially associated with HSCs and believed to provide appropriate microenvironments for HSC self-renewal, differentiation, mobilization and hibernation both by cell-cell contact and soluble factors. Interestingly, it appears that regulatory pathways governing the hematopoietic niche homeostasis are operating in the neurogenic niche as well. Therefore, this review paper aims to compare both the regulation of hematopoietic and neurogenic niches, in order to highlight the role of NCSCs and nervous system components in the development and the regulation of the hematopoietic system. PMID:26136659

  5. SPH simulation of free surface flow over a sharp-crested weir

    NASA Astrophysics Data System (ADS)

    Ferrari, Angela

    2010-03-01

    In this paper the numerical simulation of a free surface flow over a sharp-crested weir is presented. Since in this case the usual shallow water assumptions are not satisfied, we propose to solve the problem using the full weakly compressible Navier-Stokes equations with the Tait equation of state for water. The numerical method used consists of the new meshless Smooth Particle Hydrodynamics (SPH) formulation proposed by Ferrari et al. (2009) [8], that accurately tracks the free surface profile and provides monotone pressure fields. Thus, the unsteady evolution of the complex moving material interface (free surface) can been properly solved. The simulations involving about half a million of fluid particles have been run in parallel on two of the most powerful High Performance Computing (HPC) facilities in Europe. The validation of the results has been carried out analysing the pressure field and comparing the free surface profiles obtained with the SPH scheme with experimental measurements available in literature [18]. A very good quantitative agreement has been obtained.

  6. A predictive model to inform adaptive management of double-crested cormorants and fisheries in Michigan

    USGS Publications Warehouse

    Tsehaye, Iyob; Jones, Michael L.; Irwin, Brian J.; Fielder, David G.; Breck, James E.; Luukkonen, David R.

    2015-01-01

    The proliferation of double-crested cormorants (DCCOs; Phalacrocorax auritus) in North America has raised concerns over their potential negative impacts on game, cultured and forage fishes, island and terrestrial resources, and other colonial water birds, leading to increased public demands to reduce their abundance. By combining fish surplus production and bird functional feeding response models, we developed a deterministic predictive model representing bird–fish interactions to inform an adaptive management process for the control of DCCOs in multiple colonies in Michigan. Comparisons of model predictions with observations of changes in DCCO numbers under management measures implemented from 2004 to 2012 suggested that our relatively simple model was able to accurately reconstruct past DCCO population dynamics. These comparisons helped discriminate among alternative parameterizations of demographic processes that were poorly known, especially site fidelity. Using sensitivity analysis, we also identified remaining critical uncertainties (mainly in the spatial distributions of fish vs. DCCO feeding areas) that can be used to prioritize future research and monitoring needs. Model forecasts suggested that continuation of existing control efforts would be sufficient to achieve long-term DCCO control targets in Michigan and that DCCO control may be necessary to achieve management goals for some DCCO-impacted fisheries in the state. Finally, our model can be extended by accounting for parametric or ecological uncertainty and including more complex assumptions on DCCO–fish interactions as part of the adaptive management process.

  7. Fibronectin promotes differentiation of neural crest progenitors endowed with smooth muscle cell potential

    SciTech Connect

    Costa-Silva, Bruno; Coelho da Costa, Meline; Melo, Fernanda Rosene; Neves, Cynara Mendes; Alvarez-Silva, Marcio; Calloni, Giordano Wosgrau; Trentin, Andrea Goncalves

    2009-04-01

    The neural crest (NC) is a model system used to investigate multipotency during vertebrate development. Environmental factors control NC cell fate decisions. Despite the well-known influence of extracellular matrix molecules in NC cell migration, the issue of whether they also influence NC cell differentiation has not been addressed at the single cell level. By analyzing mass and clonal cultures of mouse cephalic and quail trunk NC cells, we show for the first time that fibronectin (FN) promotes differentiation into the smooth muscle cell phenotype without affecting differentiation into glia, neurons, and melanocytes. Time course analysis indicated that the FN-induced effect was not related to massive cell death or proliferation of smooth muscle cells. Finally, by comparing clonal cultures of quail trunk NC cells grown on FN and collagen type IV (CLIV), we found that FN strongly increased both NC cell survival and the proportion of unipotent and oligopotent NC progenitors endowed with smooth muscle potential. In contrast, melanocytic progenitors were prominent in clonogenic NC cells grown on CLIV. Taken together, these results show that FN promotes NC cell differentiation along the smooth muscle lineage, and therefore plays an important role in fate decisions of NC progenitor cells.

  8. Structural and stratigraphic evolution of Aleutian convergent-margin basins - ridge crest to trench floor

    SciTech Connect

    Scholl, D.W.; Ryan, H.F.; Geist, E.L.; Vallier, T.L.; Stevenson, A.J.; Childs, J.R. )

    1988-02-01

    The Aleutian Ridge lies along nearly 2000 km of the north Pacific's obliquely converging plate boundary with North America. Since middle Eocene time, convergent-margin basins have repeatedly formed here, typically as summit basins along the ridge crest, and as forearc basins on the landward trench slope. Summit and forearc basins formed as a consequence of plate-boundary coupling and the application of compressional and right-lateral shear stresses to the arc massif. Basins typically evolved along shear zones in response to transtensional processes, and as trailing-edge grabens behind rotating blocks of arc massif. In the late Cenozoic, high rates of trench sedimentation led to the growth of an accretionary complex that underthrust forearc basement. Wedging and improved plate coupling elevated and laterally shifted blocks of outer forearc rocks, creating much of the structural framework of the regionally extensive Aleutian Terrace forearc basin. Changes in plate-boundary conditions that affected the ridge's volcanic activity and regional elevation importantly influenced basinal sedimentation. Changes of greatest significance were a major shift in convergence direction and rate about 42 Ma (reduced volcanism), ridge underthrusting by increasingly younger ocean crust in Oligocene and Miocene time (arc elevation), and the combination of more orthogonal underthrusting and the subduction of a dead spreading center 5-10 Ma (arc subsidence).

  9. Structural and stratigraphic evolution of Aleutian convergent-margin basins - Ridge crest to trench floor

    SciTech Connect

    Scholl, D.W.; Ryan, H.F.; Geist, E.L.; Vallier, T.L.

    1988-01-01

    The Aleutian Ridge lies along nearly 2,000 km of the north Pacific's obliquely converging plate boundary with North America. Since middle Eocene time, convergent-margin basins have repeatedly formed here, typically as summit basins along the ridge crest, and as forecarc basins on the landward trench slope. Thick (1-4 km) sequences of terrigenous, hemipelagic, and biogenic debris have accumulated in these depressions, which are mostly intra-arc structures floored by arc-basement rocks. Summit and forearc basins formed as a consequence of plate-boundary coupling and the application of compressional and right-lateral shear stresses to the arc massif. Basins typically evolved along shear zones in response to transtensional processes, and as trailing-edge grabens behind rotating blocks of arc massif. In the late Cenozoic, high rates of trench sedimentation led to the growth of an accretionary complex that underthrust forearc basement. Wedging and improved plate coupling elevated and laterally shifted blocks of outer forearc rocks, creating much of the structural framework of the regionally extensive Aleutian Terrace forearc basin. Changes in plate-boundary conditions that affected the ridge's volcanic activity and regional elevation importantly influenced basinal sedimentation. Changes of greatest significant were a major shift in convergence direction and rate about 42 Ma (reduced volcanism), ridge underthrusting by increasingly younger ocean crust in Oligocena and Miocene time (arc elevation), and the combination of more orthogonal underthrusting and the subduction of a dead spreading center 5-120 Ma (arc subsidence).

  10. Heparan Sulfate Expression in the Neural Crest is Essential for Mouse Cardiogenesis

    PubMed Central

    Pan, Yi; Carbe, Christian; Pickhinke, Ute; Kupich, Sabine; Ohlig, Stefanie; Frye, Maike; Seelige, Ruth; Pallerla, Srinivas R.; Moon, Anne M.; Lawrence, Roger; Esko, Jeffrey D.; Zhang, Xin; Grobe, Kay

    2015-01-01

    Impaired heparan sulfate (HS) synthesis in vertebrate development causes complex malformations due to the functional disruption of multiple HS-binding growth factors and morphogens. Here, we report developmental heart defects in mice bearing a targeted disruption of the HS-generating enzyme GlcNAc N-Deacetylase/GlcN N-Sulfotransferase 1 (NDST1), including ventricular septal defects (VSD), persistent truncus arteriosus (PTA), double outlet right ventricle (DORV), and retroesophageal right subclavian artery (RERSC). These defects closely resemble cardiac anomalies observed in mice made deficient in the cardiogenic regulator fibroblast growth factor 8 (FGF8). Consistent with this, we show that HS-dependent FGF8/FGF-receptor2C assembly and FGF8-dependent ERK-phosphorylation are strongly reduced in NDST1−/− embryonic cells and tissues. Moreover, WNT1-Cre/LoxP-mediated conditional targeting of NDST function in neural crest cells (NCCs) revealed that their impaired HS-dependent development contributes strongly to the observed cardiac defects. These findings raise the possibility that defects in HS biosynthesis may contribute to congenital heart defects in humans that represent the most common type of birth defect. PMID:24200809

  11. Distribution of organochlorine contaminants in double-crested cormorant eggs and sibling embryos

    SciTech Connect

    Custer, T.W.; Custer, C.M.; Stromborg, K.L.

    1997-08-01

    Double-crested cormorant (Phalacrocorax auritus) fresh eggs and sibling embryos at pipping were collected from a polychlorinated biphenyl (PCB)-contaminated colony in Green Bay, Wisconsin, USA. Egg contents were analyzed for organochlorine (OC) contaminants, including 15 arylhydrocarbon-active PCB congeners. In order to determine the significance of tissue removal on the subsequent estimate of contaminant burden, embryos were decapitated and the heads, yolk sac, liver, fecal sac, and carcass remainder were analyzed separately. The distribution of contaminant concentration in the embryos was yolk sac > liver > carcass > head > fecal sac. The distribution of contaminant mass in the embryos was yolk sac > carcass > liver > head > fecal sac. For example, mass of total PCBs (TPCB) was yolk sac = 58%, carcass = 31%, liver = 5%, head = 3%, and fecal sac = 1%. Eighteen additional OCs, including 13 PCB congeners, had distribution patterns similar to that of TPCB concentration and mass. Excluding the head of the embryo from the chemical analysis overestimated TPCB concentrations by 15%. In contrast, excluding the liver from the chemical analysis underestimated TPCB concentration by only 4%. Mean concentrations of OCs were not significantly different between fresh eggs and sibling embryos.

  12. Vgll2a is required for neural crest cell survival during zebrafish craniofacial development

    PubMed Central

    Johnson, Christopher W.; Hernandez-Lagunas, Laura; Feng, Weiguo; Melvin, Vida Senkus; Williams, Trevor; Artinger, Kristin Bruk

    2011-01-01

    Invertebrate and vertebrate vestigial (vg) and vestigial-like (vgl) genes are involved in embryonic patterning and cell fate determination. These genes encode cofactors that interact with members of the TEAD/Scalloped family of transcription factors and modulate their activity. We have previously shown that, in mice, Vgll2 is differentially expressed in the developing facial prominences. In this study, we show that the zebrafish ortholog vgll2a is expressed in the pharyngeal endoderm and ectoderm surrounding the neural crest derived mesenchyme of the pharyngeal arches. Moreover, both the FGF and retinoic acid (RA) signaling pathways, which are critical components of the hierarchy controlling craniofacial patterning, regulate this domain of vgll2a expression. Consistent with these observations, vgll2a is required within the pharyngeal endoderm for NCC survival and pharyngeal cartilage development. Specifically, knockdown of Vgll2a in zebrafish embryos using Morpholino injection results in increased cell death within the pharyngeal arches, aberrant endodermal pouch morphogenesis, and hypoplastic cranial cartilages. Overall, our data reveal a novel non-cell autonomous role for Vgll2a in development of the NCC-derived vertebrate craniofacial skeleton. PMID:21741961

  13. Iliac crest trabecular bone mass and structure in patients with non-steroid treated rheumatoid arthritis.

    PubMed Central

    Mellish, R W; O'Sullivan, M M; Garrahan, N J; Compston, J E

    1987-01-01

    Iliac crest trabecular bone volume and structure have been studied in bone biopsy specimens from 48 patients with classical or definite rheumatoid arthritis, none of whom had received steroids. Results were compared with those obtained from healthy controls matched for age and sex. The mean trabecular bone volume in female patients aged 34-50 years was significantly lower than in controls (p less than 0.01); in male patients aged 34-50 years values were also lower than those in controls (mean (SD) 17.8 (3.2) v 22.4 (5.6)% total medullary volume), though this difference was not statistically significant. Values in older patients were similar to those of controls. The mean trabecular plate thickness was significantly lower in female patients in all three age groups when compared with the controls (p less than 0.005, 0.05, and 0.005). Similar but non-significant changes were seen in male patients. The mean trabecular plate density, an index of trabecular number, and the mean trabecular plate separation showed no age related change in either male or female patients, in contrast with the female control group, in whom the mean trabecular plate density decreased and separation increased with age. These results suggest that non-steroid treated rheumatoid arthritis is associated with premature bone loss, the structural basis of which is trabecular thinning. PMID:3426289

  14. Involvement of seven in absentia homolog-1 in ethanol-induced apoptosis in neural crest cells

    PubMed Central

    Sun, Haijing; Chen, Xiaopan; Yuan, Fuqiang; Liu, Jie; Zhao, Yingming; Chen, Shao-yu

    2014-01-01

    Ethanol-induced apoptosis in selected cell populations is a major component of pathogenesis underlying ethanol-induced teratogenesis. However, there is a fundamental gap in understanding how ethanol leads to apoptosis in embryos. In this study, we investigate the role of seven in absentia homolog-1 (Siah1) protein, an E3 ubiquitin ligase, in ethanol-induced apoptosis. Using an in vitro model of neural crest cell (NCC), JoMa1.3 cells, we found that exposure to 100 mM ethanol resulted in a significant increase in Siah1 mRNA expression in NCCs, an ethanol-sensitive cell population implicated in Fetal Alcohol Spectrum Disorders (FASD). Treatment with 100 mM ethanol for 24 hours also significantly increased the protein expression of Siah1 in JoMa1.3 cells. The nuclear translocation and accumulation of Siah1 was evidenced in the cells exposed to ethanol. In addition, we have found that the inhibition of Siah1 function with siRNA prevents ethanol-induced increase in Siah1 protein expression and nuclear translocation in NCCs. Down-regulation of Siah1 by siRNA also greatly diminished ethanol-induced cell death and caspase-3 activation, indicating that inhibition of Siah1 can attenuate ethanol-induced apoptosis. These results strongly suggest that Siah1 plays an important role in ethanol-induced apoptosis in NCCs. PMID:25193017

  15. Hmga2 is required for neural crest cell specification in Xenopus laevis.

    PubMed

    Macrì, Simone; Simula, Luca; Pellarin, Ilenia; Pegoraro, Silvia; Onorati, Marco; Sgarra, Riccardo; Manfioletti, Guidalberto; Vignali, Robert

    2016-03-01

    HMGA proteins are small nuclear proteins that bind DNA by conserved AT-hook motifs, modify chromatin architecture and assist in gene expression. Two HMGAs (HMGA1 and HMGA2), encoded by distinct genes, exist in mammals and are highly expressed during embryogenesis or reactivated in tumour progression. We here addressed the in vivo role of Xenopus hmga2 in the neural crest cells (NCCs). We show that hmga2 is required for normal NCC specification and development. hmga2 knockdown leads to severe disruption of major skeletal derivatives of anterior NCCs. We show that, within the NCC genetic network, hmga2 acts downstream of msx1, and is required for msx1, pax3 and snail2 activities, thus participating at different levels of the network. Because of hmga2 early effects in NCC specification, the subsequent epithelial-mesenchymal transition (EMT) and migration of NCCs towards the branchial pouches are also compromised. Strictly paralleling results on embryos, interfering with Hmga2 in a breast cancer cell model for EMT leads to molecular effects largely consistent with those observed on NCCs. These data indicate that Hmga2 is recruited in key molecular events that are shared by both NCCs and tumour cells. PMID:26806704

  16. The epidermal melanocyte population in the skin of ultraviolet-irradiated crested newt

    SciTech Connect

    Losa, M.; Zavanella, T.; Milani, S.

    1982-02-01

    The response of the epidermal melanocyte population to repeated ultraviolet (UV) exposure (wavelength spectrum 275-350 nm) has been investigated in the crested newt, Triturus cristatus carnifex. The effects of different doses of UV light were studied. The animals were killed 7 months after the first UV exposure. Only a slight decrease in the number of pigment cells was found after 85 sequential irradiations with a total dose of 1.3 x 10(5) J/m2, whereas striking decreases were observed when the same total dose was fractionated into 14 exposures or when a double dose was given in 57 exposures. The relationship between the square roots of the epidermal melanocyte densities and single doses appeared to be roughly linear, at least over the range of doses administered. The main factor in melanocyte damage seemed to be the single dose of irradiation rather than the cumulative dose administered. Decreased melanin content of the keratinocytes was observed in most irradiated animals.

  17. Human skin neural crest progenitor cells are susceptible to BRAFV600E-induced transformation

    PubMed Central

    Kumar, SM; Dai, J; Li, S; Yang, R; Yu, H; Nathanson, KL; Liu, S; Zhou, H; Guo, J; Xu, X

    2013-01-01

    Adult stem cells are multipotent and persist in small numbers in adult tissues throughout the lifespan of an organism. Unlike differentiated cells, adult stem cells are intrinsically resistant to senescence. It is unclear how adult stem cells in solid organs respond to oncogenic stimulation and whether these cells have a role in tumor initiation. We report here that expression of BRAFV600E in human neural crest progenitor cells (hNCPCs) did not induce growth arrest as seen in human melanocytes, but instead, increased their cell proliferation capacity. These cells (hNCPCsV600E) acquired anchorage-independent growth ability and were weakly tumorigenic in vivo. Unlike in human melanocytes, BRAFV600E expression in hNCPCs did not induce p16INK4a expression. BRAFV600E induced elevated expression of CDK2, CDK4, MITF and EST1/2 protein in hNCPCs, and also induced melanocytic differentiation of these cells. Furthermore, overexpression of MITF in hNCPCsV600E dramatically increased their tumorigenicity and resulted in fully transformed tumor cells. These findings indicate that hNCPCs are susceptible to BRAFV600E-induced transformation, and MITF potentiates the oncogenic effect of BRAFV600E in these progenitor cells. These results suggest that the hNCPCs are potential targets for BRAFV600E-induced melanocytic tumor formation. PMID:23334329

  18. Immunohistochemical and morphological features of a small bowel leiomyoma in a black crested macaque (Macaca nigra)

    PubMed Central

    2012-01-01

    Background Spontaneous gastrointestinal neoplasms in non-human primates are commonly seen in aged individuals. Due to genetic similarities between human and non-human primates, scientists have shown increasing interest in terms of comparative oncology studies. Case presentation The present study is related to a case of an intestinal leiomyoma in a black crested macaque (Macaca nigra), kept on captivity by Matecaña Zoo, Pereira City, Colombia. The animal had abdominal distension, anorexia, vomiting, diarrhea and behavioral changes. Clinical examination showed an increased volume in the upper right abdominal quadrant caused by a neoplastic mass. The patient died during the surgical procedure. Necropsy revealed several small nodules in the peritoneum with adhesion to different portions of the small and large intestines, liver, stomach and diaphragm. Tissue samples were collected, routinely processed and stained by H&E. Microscopic examination revealed a mesenchymal tumor limited to tunica muscularis, resembling normal smooth muscle cells. Neoplastic cells were positive for alpha-smooth muscle actin and vimentin, and negative for cytokeratin AE1/AE3 by immunohistochemistry. Those morphological and immunohistochemical findings allowed to diagnose the intestinal leiomyoma referred above. Conclusion Neoplastic diseases in primates have multifaceted causes. Their manifestations are understudied, leading to a greater difficulty in detection and measurement of the real impact provides by this disease. PMID:22747606

  19. Distribution of organochlorine contaminants in double-crested cormorant eggs and sibling embryos

    USGS Publications Warehouse

    Custer, T.W.; Custer, Christine M.; Stromborg, K.L.

    1997-01-01

    Double-crested cormorant (Phalacrocorax auritus) fresh eggs and sibling embryos at pipping were collected from a polychlorinated biphenyl (PCB)-contaminated colony in Green Bay, Wisconsin, USA. Egg contents were analyzed for organochlorine (OC) contaminants, including 15 arylhydrocarbon-active PCB congeners. In order to determine the significance of tissue removal on the subsequent estimate of contaminant burden, embryos were decapitated and the heads, yolk sac, liver, fecal sac (allantois), and carcass remainder were analyzed separately. The distribution of contaminant concentration in the embryos was yolk sac > liver > carcass > head > fecal sac. The distribution of contaminant mass in the embryos was yolk sac > carcass > liver > head > fecal sac. For example, mass of total PCBs (TPCB) was yolk sac = 58%, carcass = 31%, liver = 5%, head = 3%, and fecal sac = 1%. Eighteen additional OCs, including 13 PCB congeners, had distribution patterns similar to that of TPCB concentration and mass. Excluding the head of the embryo from the chemical analysis overestimated TPCB concentrations by 15% (16 vs 14 mu g/g). In contrast, excluding the liver from the chemical analysis underestimated TPCB concentration by only 4% (13.5 vs 14 mu g/g). Mean concentrations of OCs were not significantly different between fresh eggs and sibling embryos.

  20. A direct role for murine Cdx proteins in the trunk neural crest gene regulatory network.

    PubMed

    Sanchez-Ferras, Oraly; Bernas, Guillaume; Farnos, Omar; Touré, Aboubacrine M; Souchkova, Ouliana; Pilon, Nicolas

    2016-04-15

    Numerous studies in chordates and arthropods currently indicate that Cdx proteins have a major ancestral role in the organization of post-head tissues. In urochordate embryos, Cdx loss-of-function has been shown to impair axial elongation, neural tube (NT) closure and pigment cell development. Intriguingly, in contrast to axial elongation and NT closure, a Cdx role in neural crest (NC)-derived melanocyte/pigment cell development has not been reported in any other chordate species. To address this, we generated a new conditional pan-Cdx functional knockdown mouse model that circumvents Cdx functional redundancy as well as the early embryonic lethality of Cdx mutants. Through directed inhibition in the neuroectoderm, we providein vivoevidence that murine Cdx proteins impact melanocyte and enteric nervous system development by, at least in part, directly controlling the expression of the key early regulators of NC ontogenesisPax3,Msx1andFoxd3 Our work thus reveals a novel role for Cdx proteins at the top of the trunk NC gene regulatory network in the mouse, which appears to have been inherited from their ancestral ortholog. PMID:26952979

  1. Immune function, sex ratios, and gonadal histopathology in double-crested cormorant chicks

    SciTech Connect

    Burull, E.J.; Goldberg, D.R.; Sileo, L.; Dale, T.; Allen, P.D.; Stromborg, K.L.; Larson, J.X.; Fry, D.M.

    1994-12-31

    There is evidence that environmental contaminants may be associated with endocrine and reproductive system abnormalities in colonial water birds. Little information is available on immune system response in chicks. Two double-crested cormorant (Phalocrocrozax auritus) colonies were monitored in 1993 for a comparative immune function study. Higher concentrations of organochlorines occurred in one colony. Parameters measured included: CBC, T and B-cell function, heterophil phagocytosis, lymphoid organ size and histopathology, and selected serum hormone analysis. Significant differences at the contaminated site included marked dysplasia and hypertrophy of thyroid gland, higher T3, lower cortisol, lower eosinophil counts, and increase phagocytosis at the contaminated site. Gonads of 101 deformed (cross-bill) chicks, siblings, and normal control chicks collected in 1992 and 1993 were examined microscopically because a sex-ration skewed towards females had been noted. Cross-billed chicks aged 12 to 15 days had disorganized or delayed follicular development which normalized by 20 days of age. Cross-billed or otherwise abnormal chicks aged 18 to 23 days had hypertrophic seminiferous tubules, a decreased interstitium, and decreased evidence of active Leydig cells.

  2. The 1992 epizootic of Newcastle disease in double-crested cormorants in North America

    USGS Publications Warehouse

    Glaser, L.C.; Barker, I.K.; Weseloh, D.V.C.; Ludwig, J.; Windingstad, R.M.; Key, D.W.; Bollinger, T.K.

    1999-01-01

    In the summer of 1992, morbidity and mortality in juvenile double-crested cormorants (Phalacrocorax auritus; DCC) attributable to Newcastle disease virus (NDV) was observed for the first time in seven northern USA states and one Canadian province, and recurred in three western Canadian provinces. Based on clinical signs and laboratory diagnostic findings, DCC mortality from NDV occurred in 59 of the 63 nesting colonies and two of three non-colony sites investigated. An estimate of in excess of 20,000 DCC died, with mortality rates ranging from < 1 to 37% in Great Lakes colonies to 20 to 92% in Minnesota (USA) and North and South Dakota (USA) colonies. Sick juvenile white pelicans (Pelecanus erythrorhynchos) exhibiting signs similar to sick cormorants, and dead pelicans were observed in Minnesota and North Dakota. Mortality rates in pelican colonies were as high as in the adjacent cormorant colonies, but no cause for the mortality of an estimated 5,000 pelicans was determined. No evidence of NDV was found in other species nesting in proximity to affected cormorants. Although the source of the NDV infection is unknown in cormorants, the simultaneous onset of the epizootics in juvenile birds over a wide geographic area implies that the virus was acquired by adults prior to migration and was carried back to nest sites, exposing susceptible nestlings. The possible transmission of this virus from free-ranging wild birds to domestic poultry is a concern. Based on repeated epizootics in cormorants since 1990, NDV seems to be established in DCC.

  3. Erythropoietin production in neuroepithelial and neural crest cells during primitive erythropoiesis.

    PubMed

    Suzuki, Norio; Hirano, Ikuo; Pan, Xiaoqing; Minegishi, Naoko; Yamamoto, Masayuki

    2013-01-01

    Erythropoietin (Epo) supports both primitive erythropoiesis in the yolk sac and definitive erythropoiesis in the fetal liver and bone marrow. Although definitive erythropoiesis requires kidney- and liver-secreted Epo, it is unclear which cells produce Epo for primitive erythropoiesis. Here we find neural Epo-producing (NEP) cells in mid-gestational stage embryos using mouse lines that express green fluorescent protein (GFP) under the Epo gene regulation. In these mice, GFP is expressed exclusively in a subpopulation of neural and neural crest cells at embryonic day 9.0 when Epo-deficient embryos exhibit abnormalities in primitive erythropoiesis. The GFP-positive NEP cells express Epo mRNA and the ex vivo culture of embryonic day 8.5 neural tubes results in the secretion of Epo, which is able to induce the proliferation and differentiation of yolk sac-derived erythroid cells. These results thus suggest that NEP cells secrete Epo and might support the development of primitive erythropoiesis. PMID:24309470

  4. Neural Crest Stem Cells from Dental Tissues: A New Hope for Dental and Neural Regeneration

    PubMed Central

    Ibarretxe, Gaskon; Crende, Olatz; Aurrekoetxea, Maitane; García-Murga, Victoria; Etxaniz, Javier; Unda, Fernando

    2012-01-01

    Several stem cell sources persist in the adult human body, which opens the doors to both allogeneic and autologous cell therapies. Tooth tissues have proven to be a surprisingly rich and accessible source of neural crest-derived ectomesenchymal stem cells (EMSCs), which may be employed to repair disease-affected oral tissues in advanced regenerative dentistry. Additionally, one area of medicine that demands intensive research on new sources of stem cells is nervous system regeneration, since this constitutes a therapeutic hope for patients affected by highly invalidating conditions such as spinal cord injury, stroke, or neurodegenerative diseases. However, endogenous adult sources of neural stem cells present major drawbacks, such as their scarcity and complicated obtention. In this context, EMSCs from dental tissues emerge as good alternative candidates, since they are preserved in adult human individuals, and retain both high proliferation ability and a neural-like phenotype in vitro. In this paper, we discuss some important aspects of tissue regeneration by cell therapy and point out some advantages that EMSCs provide for dental and neural regeneration. We will finally review some of the latest research featuring experimental approaches and benefits of dental stem cell therapy. PMID:23093977

  5. Diagnosis and therapy of neuroblastoma and other neural crest tumors using Iodine-131-meta-iodobenzylguanidine

    SciTech Connect

    Hoefnagel, C.A.; Delprat, C.C.; De Kraker, J.; Marcuse, H.R.; Voute, P.A.

    1985-05-01

    Like pheochromocytoma, neuroblastoma is capable of synthesis and storage of catecholamines. Therefore the authors evaluated the yield of I-131-MIBG total body scintigraphy in the detection of this tumor and applied I-131-MIBG therapeutically. Total body scintigraphy was performed 24, 48 and 96 hrs after administration of 18.5 or 37 MBq I-131-MIBG. 23 patients with neuroblastoma were examined (47 studies). I-131-MIBG-scintigraphy confirmed complete remission in 7 patients and correctly detected residual/recurrent abdominal tumormasses in 5 patients and metastases in 14 patients. In 1 adult patient the scintigram was false negative. 3 children with metastatic neuroblastoma received multiple therapy doses of I-131-MIBG (1.5-3.9 GBq). Reduction of tumor size and good palliation was achieved in 2 patients with progressive disease. Intense accumulation of I-131-MIBG was observed in 1 patient with inoperable medullary thyroid carcinoma and in another with metastatic pheochromocytoma. Both received I-131-MIBG-therapy (3.7-7.9 GBq), resulting in a reduction of the tumor mass. It is concluded that I-131-MIBG, is a useful agent for diagnosis, follow up and therapy of neuroblastoma. It may occasionally be of use in therapy of other neural crest tumors and should therefore be considered when other treatment modalities are ineffective.

  6. Molecular detection of bacteria in the families Rickettsiaceae and Anaplasmataceae in northern crested caracaras (Caracara cheriway).

    PubMed

    Erwin, John A; Fitak, Robert R; Dwyer, James F; Morrison, Joan L; Culver, Melanie

    2016-04-01

    Bacterial pathogens of the families Anaplasmataceae and Rickettsiaceae are often spread to humans or other animals from bites from infected arthropod hosts. Recently, an increasing number of studies have implicated migratory birds in the circulation of these pathogens through the spread of arthropod vectors. However, few studies have examined the potential for resident bird populations to serve as reservoirs for these zoonoses. In this study, we used nested PCRs of the GroESL and 17 kDa genes to screen for Anaplasmataceae and Rickettsiaceae, respectively, in a resident population of the northern crested caracara (Caracara cheriway) from Florida (n=55). Additionally, a small number (n=6) of captive individuals from Texas were included. We identified one individual (1.64%) positive for Rickettsia felis and one (1.64%) positive for Ehrlichia chaffeensis; both these individuals were from Florida. Presence of these pathogens demonstrates that these birds are potential hosts; however, the low prevalence of infections suggests that these populations likely do not function as an ecological reservoir. PMID:26837860

  7. Recapitulating cranial osteogenesis with neural crest cells in 3-D microenvironments.

    PubMed

    Namkoong, Bumjin; Güven, Sinan; Ramesan, Shwathy; Liaudanskaya, Volha; Abzhanov, Arhat; Demirci, Utkan

    2016-02-01

    The experimental systems that recapitulate the complexity of native tissues and enable precise control over the microenvironment are becoming essential for the pre-clinical tests of therapeutics and tissue engineering. Here, we described a strategy to develop an in vitro platform to study the developmental biology of craniofacial osteogenesis. In this study, we directly osteo-differentiated cranial neural crest cells (CNCCs) in a 3-D in vitro bioengineered microenvironment. Cells were encapsulated in the gelatin-based photo-crosslinkable hydrogel and cultured up to three weeks. We demonstrated that this platform allows efficient differentiation of p75 positive CNCCs to cells expressing osteogenic markers corresponding to the sequential developmental phases of intramembranous ossification. During the course of culture, we observed a decrease in the expression of early osteogenic marker Runx2, while the other mature osteoblast and osteocyte markers such as Osterix, Osteocalcin, Osteopontin and Bone sialoprotein increased. We analyzed the ossification of the secreted matrix with alkaline phosphatase and quantified the newly secreted hydroxyapatite. The Field Emission Scanning Electron Microscope (FESEM) images of the bioengineered hydrogel constructs revealed the native-like osteocytes, mature osteoblasts, and cranial bone tissue morphologies with canaliculus-like intercellular connections. This platform provides a broadly applicable model system to potentially study diseases involving primarily embryonic craniofacial bone disorders, where direct diagnosis and adequate animal disease models are limited. PMID:26675129

  8. Induction of neural crest in Xenopus by transcription factor AP2alpha.

    PubMed

    Luo, Ting; Lee, Young-Hoon; Saint-Jeannet, Jean-Pierre; Sargent, Thomas D

    2003-01-21

    We report experiments with Xenopus laevis, using both intact embryos and ectodermal explants, showing that the transcription factor AP2alpha is positively regulated by bone morphogenetic protein (BMP) and Wnt signaling, and that this activation is an essential step in the induction of neural crest (NC). Ectopic expression of AP2alpha is sufficient to activate high-level expression of NC-specific genes such as Slug and Sox9, which can occur as isolated domains within the neural plate as well as by expansion of endogenous NC territories. AP2alpha also has the property of inducing NC in isolated ectoderm in which Wnt signaling is provided but BMP signaling is minimized by overexpression of chordin. Like other NC regulatory factors, activation of AP2alpha requires some attenuation of endogenous BMP signaling; however, this process occurs at a lower threshold for AP2alpha. Furthermore, AP2alpha expression domains are larger than for other NC factors. Loss-of-function experiments with antisense AP2alpha morpholino oligonucleotides result in severe reduction in the NC territory. These results support a central role for AP2alpha in NC induction. We propose a model in which AP2alpha expression, along with inactivation of NC inhibitory factors such as Dlx3, establish a feedback loop comprising AP2alpha, Sox9, and Slug, leading to and maintaining NC specification. PMID:12511599

  9. Functional Interaction Between Foxd3 and Pax3 in Cardiac Neural Crest Development

    PubMed Central

    Nelms, Brian L.; Pfaltzgraff, Elise R.; Labosky, Patricia A.

    2011-01-01

    Summary The transcription factors Foxd3 and Pax3 are important early regulators of neural crest (NC) progenitor cell properties. Homozygous mutations of Pax3 or a homozygous NC-specific deletion of Foxd3 cause marked defects in most NC derivatives, but neither loss of both Foxd3 alleles nor loss of one Pax3 allele alone greatly affects overall development of cardiac NC derivatives. In contrast, compound mutant embryos homozygous for a NC-specific Foxd3 mutation and heterozygous for Pax3 have fully penetrant persistent truncus arteriosus, severe thymus hypoplasia, and midgestation lethality. Foxd3; Pax3 compound mutant embryos have increased cell death in the neural folds and a drastic early reduction of NC cells, with an almost complete absence of NC caudal to the first pharyngeal arch. The genetic interaction between these genes implicates gene dosage-sensitive roles for Foxd3 and Pax3 in cardiac NC progenitors. Foxd3 and Pax3 act together to affect survival and maintenance of cardiac NC progenitors, and loss of these progenitors catastrophically affects key aspects of later cardiovascular development. PMID:21254333

  10. Neural crest stem cell multipotency requires Foxd3 to maintain neural potential and repress mesenchymal fates.

    PubMed

    Mundell, Nathan A; Labosky, Patricia A

    2011-02-01

    Neural crest (NC) progenitors generate a wide array of cell types, yet molecules controlling NC multipotency and self-renewal and factors mediating cell-intrinsic distinctions between multipotent versus fate-restricted progenitors are poorly understood. Our earlier work demonstrated that Foxd3 is required for maintenance of NC progenitors in the embryo. Here, we show that Foxd3 mediates a fate restriction choice for multipotent NC progenitors with loss of Foxd3 biasing NC toward a mesenchymal fate. Neural derivatives of NC were lost in Foxd3 mutant mouse embryos, whereas abnormally fated NC-derived vascular smooth muscle cells were ectopically located in the aorta. Cranial NC defects were associated with precocious differentiation towards osteoblast and chondrocyte cell fates, and individual mutant NC from different anteroposterior regions underwent fate changes, losing neural and increasing myofibroblast potential. Our results demonstrate that neural potential can be separated from NC multipotency by the action of a single gene, and establish novel parallels between NC and other progenitor populations that depend on this functionally conserved stem cell protein to regulate self-renewal and multipotency. PMID:21228004

  11. Neural crest stem cell multipotency requires Foxd3 to maintain neural potential and repress mesenchymal fates

    PubMed Central

    Mundell, Nathan A.; Labosky, Patricia A.

    2011-01-01

    Neural crest (NC) progenitors generate a wide array of cell types, yet molecules controlling NC multipotency and self-renewal and factors mediating cell-intrinsic distinctions between multipotent versus fate-restricted progenitors are poorly understood. Our earlier work demonstrated that Foxd3 is required for maintenance of NC progenitors in the embryo. Here, we show that Foxd3 mediates a fate restriction choice for multipotent NC progenitors with loss of Foxd3 biasing NC toward a mesenchymal fate. Neural derivatives of NC were lost in Foxd3 mutant mouse embryos, whereas abnormally fated NC-derived vascular smooth muscle cells were ectopically located in the aorta. Cranial NC defects were associated with precocious differentiation towards osteoblast and chondrocyte cell fates, and individual mutant NC from different anteroposterior regions underwent fate changes, losing neural and increasing myofibroblast potential. Our results demonstrate that neural potential can be separated from NC multipotency by the action of a single gene, and establish novel parallels between NC and other progenitor populations that depend on this functionally conserved stem cell protein to regulate self-renewal and multipotency. PMID:21228004

  12. Receptor Tyrosine Kinase Signaling: Regulating Neural Crest Development One Phosphate at a Time

    PubMed Central

    Fantauzzo, Katherine A.; Soriano, Philippe

    2015-01-01

    Receptor tyrosine kinases (RTKs) bind to a subset of growth factors on the surface of cells and elicit responses with broad roles in developmental and postnatal cellular processes. Receptors in this subclass consist of an extracellular ligand-binding domain, a single transmembrane domain, and an intracellular domain harboring a catalytic tyrosine kinase and regulatory sequences that are phosphorylated either by the receptor itself or various interacting proteins. Once activated, RTKs bind signaling molecules and recruit effector proteins to mediate downstream cellular responses through various intracellular signaling pathways. In this chapter, we will highlight the role of a subset of RTK families in regulating the activity of neural crest cells (NCCs) and the development of their derivatives in mammalian systems. NCCs are migratory, multipotent cells that can be subdivided into four axial populations, cranial, cardiac, vagal and trunk. These cells migrate throughout the vertebrate embryo along defined pathways and give rise to unique cell types and structures. Interestingly, individual RTK families often have specific functions in a subpopulation of NCCs that contribute to the diversity of these cells and their derivatives in the mammalian embryo. We will additionally discuss current methods used to investigate RTK signaling, including genetic, biochemical, large-scale proteomic and biosensor approaches, which can be applied to study intracellular signaling pathways active downstream of this receptor subclass during NCC development. PMID:25662260

  13. The "domestication syndrome" in mammals: a unified explanation based on neural crest cell behavior and genetics.

    PubMed

    Wilkins, Adam S; Wrangham, Richard W; Fitch, W Tecumseh

    2014-07-01

    Charles Darwin, while trying to devise a general theory of heredity from the observations of animal and plant breeders, discovered that domesticated mammals possess a distinctive and unusual suite of heritable traits not seen in their wild progenitors. Some of these traits also appear in domesticated birds and fish. The origin of Darwin's "domestication syndrome" has remained a conundrum for more than 140 years. Most explanations focus on particular traits, while neglecting others, or on the possible selective factors involved in domestication rather than the underlying developmental and genetic causes of these traits. Here, we propose that the domestication syndrome results predominantly from mild neural crest cell deficits during embryonic development. Most of the modified traits, both morphological and physiological, can be readily explained as direct consequences of such deficiencies, while other traits are explicable as indirect consequences. We first show how the hypothesis can account for the multiple, apparently unrelated traits of the syndrome and then explore its genetic dimensions and predictions, reviewing the available genetic evidence. The article concludes with a brief discussion of some genetic and developmental questions raised by the idea, along with specific predictions and experimental tests. PMID:25024034

  14. Developing nondestructive techniques for managing conflicts between fisheries and double-crested cormorant colonies

    USGS Publications Warehouse

    Suzuki, Yasuko; Roby, Daniel D.; Lyons, Donald E.; Courtot, Karen; Collis, Ken

    2015-01-01

    Double-crested cormorants (Phalacrocorax auritus) have been identified as the source of significant mortality to juvenile salmonids (Oncorhynchus spp.) in the Columbia River Basin. Management plans for reducing the size of a large colony on East Sand Island (OR, USA) in the Columbia River estuary are currently being developed. We evaluated habitat enhancement and social attraction as nondestructive techniques for managing cormorant nesting colonies during 2004–2007. We tested these techniques on unoccupied plots adjacent to the East Sand Island cormorant colony. Cormorants quickly colonized these plots and successfully raised young. Cormorants also were attracted to nest and raised young on similar plots at 2 islands approximately 25 km from East Sand Island; 1 island had a history of successful cormorant nesting whereas the other was a site where cormorants had previously nested unsuccessfully. On a third island with no history of cormorant nesting or nesting attempts, these techniques were unsuccessful at attracting cormorants to nest. Our results suggest that some important factors influencing attraction of nesting cormorants using these techniques include history of cormorant nesting, disturbance, and presence of breeding cormorants nearby. These techniques may be effective in redistributing nesting cormorants away from areas where fish stocks of conservation concern are susceptible to predation, especially if sites with a recent history of cormorant nesting are available within their foraging or dispersal range. Published 2015. Wiley Periodicals, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America.

  15. Controlled levels of canonical Wnt signaling are required for neural crest migration.

    PubMed

    Maj, Ewa; Künneke, Lutz; Loresch, Elisabeth; Grund, Anita; Melchert, Juliane; Pieler, Tomas; Aspelmeier, Timo; Borchers, Annette

    2016-09-01

    Canonical Wnt signaling plays a dominant role in the development of the neural crest (NC), a highly migratory cell population that generates a vast array of cell types. Canonical Wnt signaling is required for NC induction as well as differentiation, however its role in NC migration remains largely unknown. Analyzing nuclear localization of β-catenin as readout for canonical Wnt activity, we detect nuclear β-catenin in premigratory but not migratory Xenopus NC cells suggesting that canonical Wnt activity has to decrease to basal levels to enable NC migration. To define a possible function of canonical Wnt signaling in Xenopus NC migration, canonical Wnt signaling was modulated at different time points after NC induction. This was accomplished using either chemical modulators affecting β-catenin stability or inducible glucocorticoid fusion constructs of Lef/Tcf transcription factors. In vivo analysis of NC migration by whole mount in situ hybridization demonstrates that ectopic activation of canonical Wnt signaling inhibits cranial NC migration. Further, NC transplantation experiments confirm that this effect is tissue-autonomous. In addition, live-cell imaging in combination with biophysical data analysis of explanted NC cells confirms the in vivo findings and demonstrates that modulation of canonical Wnt signaling affects the ability of NC cells to perform single cell migration. Thus, our data support the hypothesis that canonical Wnt signaling needs to be tightly controlled to enable migration of NC cells. PMID:27341758

  16. The SWI/SNF BAF-A complex is essential for neural crest development.

    PubMed

    Chandler, Ronald L; Magnuson, Terry

    2016-03-01

    Growing evidence indicates that chromatin remodeler mutations underlie the pathogenesis of human neurocristopathies or disorders that affect neural crest cells (NCCs). However, causal relationships among chromatin remodeler subunit mutations and NCC defects remain poorly understood. Here we show that homozygous loss of ARID1A-containing, SWI/SNF chromatin remodeling complexes (BAF-A) in NCCs results in embryonic lethality in mice, with mutant embryos succumbing to heart defects. Strikingly, monoallelic loss of ARID1A in NCCs led to craniofacial defects in adult mice, including shortened snouts and low set ears, and these defects were more pronounced following homozygous loss of ARID1A, with the ventral cranial bones being greatly reduced in size. Early NCC specification and expression of the BRG1 NCC target gene, PLEXINA2, occurred normally in the absence of ARID1A. Nonetheless, mutant embryos displayed incomplete conotruncal septation of the cardiac outflow tract and defects in the posterior pharyngeal arteries, culminating in persistent truncus arteriosus and agenesis of the ductus arteriosus. Consistent with this, migrating cardiac NCCs underwent apoptosis within the circumpharyngeal ridge. Our data support the notion that multiple, distinct chromatin remodeling complexes govern genetically separable events in NCC development and highlight a potential pathogenic role for NCCs in the human BAF complex disorder, Coffin-Siris Syndrome. PMID:26806701

  17. Multi-frequency simultaneous measurement of bioimpedance spectroscopy based on a low crest factor multisine excitation.

    PubMed

    Yang, Yuxiang; Zhang, Fu; Tao, Kun; Wang, Lianhuan; Wen, He; Teng, Zhaosheng

    2015-03-01

    Bioimpedance spectroscopy (BIS) is becoming a powerful diagnostic tool for a wide variety of medical applications, and the multi-frequency simultaneous (MFS) measurement of BIS can greatly reduce measurement time and record the transient physiological status of a living body compared with traditional frequency-sweep measurement technology. This paper adopts the Van der Ouderaa's multisine, which has 31 equidistant and flat amplitude spectra and a low crest factor of 1.405 as the broadband excitation, and realizes the MFS measurement of BIS by means of spectral analysis using the fast Fourier transform algorithm. The approach to implement the multisine based on a field-programmable gate array and a digital to analog converter is described in detail, and impedance measurement experiments are performed on three resistance-capitance three-element phantoms. Experimental results show a commendable accuracy with a mean relative error of 0.55% for the impedance amplitudes, and a mean absolute error of 0.20° for the impedance phases on the 31 frequencies ranging linearly from 32 to 992 kHz. This paper validates the feasibility of the MFS technology for BIS measurement based on the multisine excitation. PMID:25679488

  18. Neural Crest-Specific TSC1 Deletion in Mice Leads to Sclerotic Craniofacial Bone Lesion.

    PubMed

    Fang, Fang; Sun, Shaogang; Wang, Li; Guan, Jun-Lin; Giovannini, Marco; Zhu, Yuan; Liu, Fei

    2015-07-01

    Tuberous sclerosis complex (TSC) is an autosomal dominant disorder caused by mutations in either TSC1 or TSC2. TSC has high frequency of osseous manifestations such as sclerotic lesions in the craniofacial region. However, an animal model that replicates TSC craniofacial bone lesions has not yet been described. The roles of Tsc1 and the sequelae of Tsc1 dysfunction in bone are unknown. In this study, we generated a mouse model of TSC with a deletion of Tsc1 in neural crest-derived (NCD) cells that recapitulated the sclerotic craniofacial bone lesions in TSC. Analysis of this mouse model demonstrated that TSC1 deletion led to enhanced mTORC1 signaling in NCD bones and the increase in bone formation is responsible for the aberrantly increased bone mass. Lineage mapping revealed that TSC1 deficient NCD cells overpopulated the NCD bones. Mechanistically, hyperproliferation of osteoprogenitors at an early postnatal stage accounts for the increased osteoblast pool. Intriguingly, early postnatal treatment with rapamycin, an mTORC1 inhibitor, can completely rescue the aberrant bone mass, but late treatment cannot. Our data suggest that enhanced mTOR signaling in NCD cells can increase bone mass through enlargement of the osteoprogenitor pool, which likely explains the sclerotic bone lesion observed in TSC patients. PMID:25639352

  19. Voltage-dependent potassium currents in developing neurones from quail mesencephalic neural crest.

    PubMed Central

    Bader, C R; Bertrand, D; Dupin, E

    1985-01-01

    Neurones in explants cultured from quail mesencephalic neural crest were studied at different stages of their development using the voltage-clamp technique. A voltage-dependent outward current activated by membrane depolarization was identified as a potassium current by the sensitivity of its reversal potential to extracellular potassium. The voltage-dependent potassium current is made up of two components which differ in their sensitivity to 4-aminopyridine (4-AP) and tetraethylammonium (TEA). The component most sensitive to 4-AP has fast activation kinetics and inactivates quickly at sustained depolarized voltages. By analogy with a current described in other preparations, this current was called IA. The component most sensitive to TEA has slower activation kinetics and inactivates more slowly at sustained depolarized voltages. This current was called IK. IA and IK were already present in neurones cultured for 24 h. The ratio between the peak of IK and that of IA increased significantly between 24 h and 4 days in culture. This means that the two components of the voltage-dependent potassium current follow a different time course during development. Images Plate 1 PMID:2414432

  20. The crooked nose: the use of medial iliac crest bone graft as a supporting framework.

    PubMed

    Cil, Yakup; Ozturk, Serdar; Kocman, Atacan Emre; Isik, Selcuk; Sengezer, Mustafa

    2008-11-01

    The crooked nose is one that the vertical axis of the nose inclines from the midline. As a rule, a major septal deformity almost always accompanies to impairing breathing and aesthetic appearance. To achieve total straightening of the crooked nose, the septum must become the target of the treatment. To prevent redeviation, we used rigid bone grafts instead of flexible and relatively weak cartilage to maintain the support of the corrected deformity. Between February 2005 and July 2007, 9 patients (all male) with crooked noses underwent corrective surgery. The mean age of the patients was 21 years (range, 19-23 years). The source of the bone graft was medial side of iliac crest in all patients. The mean follow-up was 18 months, ranging from 10 to 26 months. All patients had both functional and cosmetic problems. Mean operation time was 4 hours. Airway patency was improved in all cases. The grafts did not shift in any case and did not develop unsightly irregularities over time. Absorption of the grafts was not seen in the follow-up. There were no cases of extrusion or infection. No donor site complication occurred. None of the patient required secondary surgery. A residual deviation can be obvious despite all attempts, which has no deleterious effect on patient satisfaction. This article introduces a novel technique for the correction of the crooked nose. PMID:19098567

  1. Lrig3 regulates neural crest formation in Xenopus by modulating Fgf and Wnt signaling pathways.

    PubMed

    Zhao, Hui; Tanegashima, Kosuke; Ro, Hyunju; Dawid, Igor B

    2008-04-01

    Leucine-rich repeats and immunoglobulin-like domains 3 (Lrig3) was identified by microarray analysis among genes that show differential expression during gastrulation in Xenopus laevis. Lrig3 was expressed in the neural plate and neural crest (NC) at neurula stages, and in NC derivatives and other dorsal structures during tailbud stages. A prominent consequence of the morpholino-induced inhibition of Lrig3 expression was impaired NC formation, as revealed by the suppression of marker genes, including Slug, Sox9 and Foxd3. In the NC induction assay involving Chordin plus Wnt3a-injected animal caps, Lrig3 morpholino inhibited expression of Slug, Sox9 and Foxd3, but not of Pax3 and Zic1. In line with this, Lrig3 knockdown prevented NC marker induction by Pax3 and Zic1, suggesting that Lrig3 acts downstream of these two genes in NC formation. Injection of Lrig3 and Wnt3a led to low-level induction of NC markers and enhanced induction of Fgf3, Fgf4 and Fgf8 in animal caps, suggesting a positive role for Lrig3 in Wnt signaling. Lrig3 could attenuate Fgf signaling in animal caps, did interact with Fgf receptor 1 in cultured cells and, according to context, decreased or increased the induction of NC markers by Fgf. We suggest that Lrig3 functions in NC formation in Xenopus by modulating the Wnt and Fgf signaling pathways. PMID:18287203

  2. Lrig3 regulates neural crest formation in Xenopus by modulating Fgf and Wnt signaling pathways

    PubMed Central

    Zhao, Hui; Tanegashima, Kosuke; Ro, Hyunju; Dawid, Igor B.

    2009-01-01

    Leucine-rich repeats and immunoglobulin-like domains 3 (Lrig3) was identified by microarray analysis among genes that show differential expression during gastrulation in Xenopus laevis. Lrig3 was expressed in the neural plate and neural crest (NC) at neurula stages, and in NC derivatives and other dorsal structures during tailbud stages. A prominent consequence of the morpholino-induced inhibition of Lrig3 expression was impaired NC formation, as revealed by the suppression of marker genes, including Slug, Sox9 and Foxd3. In the NC induction assay involving Chordin plus Wnt3a-injected animal caps, Lrig3 morpholino inhibited expression of Slug, Sox9 and Foxd3, but not of Pax3 and Zic1. In line with this, Lrig3 knockdown prevented NC marker induction by Pax3 and Zic1, suggesting that Lrig3 acts downstream of these two genes in NC formation. Injection of Lrig3 and Wnt3a led to low-level induction of NC markers and enhanced induction of Fgf3, Fgf4 and Fgf8 in animal caps, suggesting a positive role for Lrig3 in Wnt signaling. Lrig3 could attenuate Fgf signaling in animal caps, did interact with Fgf receptor 1 in cultured cells and, according to context, decreased or increased the induction of NC markers by Fgf. We suggest that Lrig3 functions in NC formation in Xenopus by modulating the Wnt and Fgf signaling pathways. PMID:18287203

  3. Fibulin-1 is required for morphogenesis of neural crest-derived structures

    PubMed Central

    Cooley, Marion A.; Kern, Christine B.; Fresco, Victor M.; Wessels, Andy; Thompson, Robert P.; McQuinn, Tim C.; Twal, Waleed O.; Mjaatvedt, Corey H.; Drake, Christopher J.; Argraves, W. Scott

    2008-01-01

    Here we report that mouse embryos homozygous for a gene trap insertion in the fibulin-1 (Fbln1) gene are deficient in Fbln1 and exhibit cardiac ventricular wall thinning and ventricular septal defects with double outlet right ventricle or overriding aorta. Fbln1 nulls also display anomalies of aortic arch arteries, hypoplasia of the thymus and thyroid, underdeveloped skull bones, malformations of cranial nerves and hemorrhagic blood vessels in the head and neck. The spectrum of malformations is consistent with Fbln1 influencing neural crest cell (NCC)-dependent development of these tissues. This is supported by evidence that Fbln1 expression is associated with streams of cranial NCCs migrating adjacent to rhombomeres 2–7 and that Fbln1-deficient embryos display patterning anomalies of NCCs forming cranial nerves IX and X, which derive from rhombomeres 6 and 7. Additionally, Fbln1-deficient embryos show increased apoptosis in areas populated by NCCs derived from rhombomeres 4, 6 and 7. Based on these findings, it is concluded that Fbln1 is required for the directed migration and survival of cranial NCCs contributing to the development of pharyngeal glands, craniofacial skeleton, cranial nerves, aortic arch arteries, cardiac outflow tract and cephalic blood vessels. PMID:18538758

  4. MycN Is Critical for the Maintenance of Human Embryonic Stem Cell-Derived Neural Crest Stem Cells.

    PubMed

    Zhang, Jie Ting; Weng, Zhi Hui; Tsang, Kam Sze; Tsang, Lai Ling; Chan, Hsiao Chang; Jiang, Xiao Hua

    2016-01-01

    The biologic studies of human neural crest stem cells (hNCSCs) are extremely challenging due to the limited source of hNCSCs as well as ethical and technical issues surrounding isolation of early human embryonic tissues. On the other hand, vast majority of studies on MycN have been conducted in human tumor cells, thus, the role of MycN in normal human neural crest development is completely unknown. In the present study, we determined the role of MycN in hNCSCs isolated from in vitro-differentiating human embryonic stem cells (hESCs). For the first time, we show that suppression of MycN in hNCSCs inhibits cell growth and cell cycle progression. Knockdown of MycN in hNCSCs increases the expression of Cdkn1a, Cdkn2a and Cdkn2b, which encodes the cyclin-dependent kinases p21CIP1, p16 INK4a and p15INK4b. In addition, MycN is involved in the regulation of human sympathetic neurogenesis, as knockdown of MycN enhances the expression of key transcription factors involved in sympathetic neuron differentiation, including Phox2a, Phox2b, Mash1, Hand2 and Gata3. We propose that unlimited source of hNCSCs provides an invaluable platform for the studies of human neural crest development and diseases. PMID:26815535

  5. A Calcium-dependent switch in a CREST-BRG1 complex regulates activity-dependent gene expression

    PubMed Central

    Qiu, Zilong; Ghosh, Anirvan

    2009-01-01

    Activity-dependent gene expression plays an important role in mediating the effects of sensory experience on nervous system development and function. While several activity-dependent transcription factors have been identified, the mechanism by which calcium signaling converts a promoter from a silenced to an active state is not well understood. Here we show that a CREST-BRG1 complex plays a critical role in regulating promoter activation by orchestrating a calcium-dependent release of a repressor complex, and a recruitment of an activator complex. In resting neurons, transcription of the c-fos promoter is inhibited by BRG1-dependent recruitment of a phospho-Rb-HDAC repressor complex. Upon calcium influx, Rb becomes dephosphorylated at Serine 795 by Calcineurin, which leads to release of the repressor complex. At the same time there is increased recruitment of CBP to the promoter by a CREST-dependent mechanism, which leads to transcriptional activation. The CREST-BRG1 also binds to the NR2B promoter and activity-dependent induction of NR2B expression involves a release of HDAC1 and recruitment of CBP, suggesting that this mechanism may be generally involved in regulating calcium-dependent transcription of neuronal genes. PMID:19081374

  6. Evaluation of Satellite-based Global Hydrologic Simulation using the Distributed CREST Model and Global Runoff Data Centre Archives

    NASA Astrophysics Data System (ADS)

    Xue, X.; Hong, Y.; Gourley, J. J.; Wang, X.

    2011-12-01

    Flooding is one of the most deadly natural hazards around the world. Distributed hydrologic models can provide the spatial and temporal distribution of precipitation, soil moisture, evapotranspiration and runoff. Implementation of a flood prediction and/or forecast system using a distributed hydrologic model can potentially help mitigate flood-induced hazards. In this study, we propose the use of the Coupled Routing and Excess STorage (CREST) distributed hydrological model driven by real-time rainfall forcing from TRMM-based multi-satellite products and/or precipitation forecast data from the Global Forecast System model (GFS), combined with automatic parameter optimization methods, to estimate hydrological fluxes, storages and inundated areas. Evaluations show that: 1) the capability of real-time streamflow prediction and/or forecast at drainage outlets and identification of inundated areas upstream is an achievable goal even for ungauged basins; 2) a-priori, physically-based parameter estimates with CREST reduce the dependence on rainfall-runoff data often required to calibrate distributed hydrologic models; and 3) the validation of CREST simulations of basin discharge are skillful in several basins throughout the world.

  7. Crest - A Balloon-borne Instrument To Measure Cosmic-ray Electrons Above TeV Energies.

    NASA Astrophysics Data System (ADS)

    Schubnell, Michael; Anderson, T.; Bower, C.; Coutu, S.; Geske, M.; Müller, D.; Musser, J.; Nutter, S.; Park, N.; Tarlé, G.; Wakely, S.; Yagi, A.

    2009-01-01

    The observation of high energy (E > 1 TeV) electrons in the cosmic radiation provides important information on the distribution and energetics of local cosmic-ray sources. Galactic cosmic-ray electrons are thought to be shock accelerated in supernova remnants as evident from observations of non-thermal X-rays and TeV gamma rays. Their locally observed energy spectrum above 1 TeV is expected to reflect the distribution and abundance of nearby acceleration sites. However, the rates at these energies are low and the direct detection would require unfeasibly large balloons or satellite born detectors. CREST, a balloon-borne detector array of 1024 BaF2 crystals, overcomes this hurdle: it will measure the intensity and spectrum of multi-TeV electrons by detecting synchrotron photons emitted from electrons passing through the earth's magnetic field. Thus CREST's acceptance is several times its geometric area providing sensitivity up to about 50 TeV. Following an engineering flight in spring of 2009, CREST will be flown in a circumpolar orbit on an upcoming Antarctic long-duration balloon flight. This work is supported by NASA and CSBF.

  8. Predation on giant flying squirrels (Petaurista philippensis) by black crested gibbons (Nomascus concolor jingdongensis) at Mt. Wuliang, Yunnan, China.

    PubMed

    Fan, Peng-Fei; Jiang, Xue-Long

    2009-01-01

    Predation on vertebrates is infrequent in gibbons. In a 14-month field study of the central Yunnan black crested gibbon (Nomascus concolor jingdongensis) at Mt. Wuliang, Yunnan, China, we observed gibbons attacking, killing and eating giant flying squirrels (Petaurista philippensis). During 845 h of observation on one study group, the gibbons attacked giant flying squirrels 11 times, and succeeded in 4 cases. Although all members of the group attempted to attack the squirrels, all four successful attacks were made by the same adult female. The victims were infants in three cases and a juvenile or sub-adult in one case. Black crested gibbons also attacked adult giant flying squirrels by grabbing their long tails and throwing them from the canopy, but they failed to catch or kill the prey in three cases observed. Passive meat sharing occurred in three out of four successful cases. Besides hunting giant flying squirrels, the black crested gibbons also ate eggs or chicks in two birds' nests and one lizard. PMID:19015936

  9. Balancing on the Crest - evidence for disruption of the enteric ganglia via inappropriate lineage segregation and consequences for gastrointestinal function

    PubMed Central

    Musser, Melissa A.; Southard-Smith, E. Michelle

    2013-01-01

    Normal enteric nervous system (ENS) development relies on numerous factors, including appropriate migration, proliferation, differentiation, and maturation of neural crest (NC) derivatives. Incomplete rostral to caudal migration of enteric neural crest-derived progenitors (ENPs) down the gut is at least partially responsible for the absence of enteric ganglia that is a hallmark feature of Hirschsprung disease (HSCR). The thought that ganglia proximal to aganglionosis are normal has guided surgical procedures for HSCR patients. However, chronic gastrointestinal dysfunction suffered by a subset of patients after surgery as well as studies in HSCR mouse models suggest that aberrant NC segregation and differentiation may be occurring in ganglionated regions of the intestine. Studies in mouse models that possess enteric ganglia throughout the length of the intestine (non-HSCR) have also found that certain genetic alterations affect neural crest lineage balance and interestingly many of these mutants also have functional gastrointestinal (GI) defects. It is possible that many GI disorders can be explained in part by imbalances in NC-derived lineages. Here we review studies evaluating ENS defects in HSCR and non-HSCR mouse models, concluding with clinical implications while highlighting areas requiring further study. PMID:23376538

  10. SNW1 is a critical regulator of spatial BMP activity, neural plate border formation, and neural crest specification in vertebrate embryos.

    PubMed

    Wu, Mary Y; Ramel, Marie-Christine; Howell, Michael; Hill, Caroline S

    2011-01-01

    Bone morphogenetic protein (BMP) gradients provide positional information to direct cell fate specification, such as patterning of the vertebrate ectoderm into neural, neural crest, and epidermal tissues, with precise borders segregating these domains. However, little is known about how BMP activity is regulated spatially and temporally during vertebrate development to contribute to embryonic patterning, and more specifically to neural crest formation. Through a large-scale in vivo functional screen in Xenopus for neural crest fate, we identified an essential regulator of BMP activity, SNW1. SNW1 is a nuclear protein known to regulate gene expression. Using antisense morpholinos to deplete SNW1 protein in both Xenopus and zebrafish embryos, we demonstrate that dorsally expressed SNW1 is required for neural crest specification, and this is independent of mesoderm formation and gastrulation morphogenetic movements. By exploiting a combination of immunostaining for phosphorylated Smad1 in Xenopus embryos and a BMP-dependent reporter transgenic zebrafish line, we show that SNW1 regulates a specific domain of BMP activity in the dorsal ectoderm at the neural plate border at post-gastrula stages. We use double in situ hybridizations and immunofluorescence to show how this domain of BMP activity is spatially positioned relative to the neural crest domain and that of SNW1 expression. Further in vivo and in vitro assays using cell culture and tissue explants allow us to conclude that SNW1 acts upstream of the BMP receptors. Finally, we show that the requirement of SNW1 for neural crest specification is through its ability to regulate BMP activity, as we demonstrate that targeted overexpression of BMP to the neural plate border is sufficient to restore neural crest formation in Xenopus SNW1 morphants. We conclude that through its ability to regulate a specific domain of BMP activity in the vertebrate embryo, SNW1 is a critical regulator of neural plate border formation and

  11. Modeling the Flushing Response to the Construction of a Low Crested Weir in the Banana River

    NASA Astrophysics Data System (ADS)

    Saberi, A.; Weaver, R. J.

    2014-12-01

    The ADCIRC hydrodynamic model coupled with a Lagrangian Particle Tracking Model (LPTM) is applied to study circulation in the Banana River. The purpose of this study is to determine the extent to which constructing a low crested weir adjacent to Port Canaveral can improve flushing in this region. The Banana River a 50 km long sub-basin of the Indian River Lagoon (IRL), located on the central-east coast of Florida in Brevard County between Cape Canaveral and Merritt Island. Although Banana River has an outlet to the ocean through the Port Canaveral locks, the locks remain closed when there is no passing vessel resulting in limited circulation, long flushing time and poor water quality. Recent high mortality events of different species, e.g. dolphins, manatees and pelicans in the lagoon ecosystem, can be linked to the decline in the water quality. ADCIRC is used to simulate the hydrodynamic properties of the study area and determine the 2D depth-averaged velocity field for two separate cases: one with only tidal and another with both tidal and meteorological forces considered. Simulations are run, first to establish the baseline hydrodynamics of the unmodified system, and then to predict the effects of modifying the domain. Passive particles are placed in the Banana River portion of our domain, and the movement of these particles is tracked using LPTM for both cases. Flushing and residence time are then computed. Results indicate an improvement in flushing in both the Banana River and the central Indian River Lagoon, driven by an induced southerly current. In the portion of the Banana River to the south of the port complex, tidal flushing time is significantly reduced for the case of modified domain. In this southern region the flushing time based on 50% renewal time, is decreased from 100 days down to 15 days, after the addition of the weir to the domain.

  12. Foraging location and site fidelity of the Double-crested Cormorant on Oneida Lake, New York

    USGS Publications Warehouse

    Coleman, J.T.H.; Richmond, M.E.; Rudstam, L. G.; Mattison, P.M.

    2005-01-01

    We studied the foraging behavior of the Double-crested Cormorant (Phalacrocorax auritus) on Oneida Lake, New York, by monitoring the activities of 27 radio-tagged birds in July and August of 1999 and 2000. A total of 224 locations were obtained of cormorants actively diving, and presumed foraging, at the time of detection. A geographic information system was used to examine foraging distances from the nesting island, the water depth and type of substrate at preferred foraging sites, and to estimate kernel home ranges for analysis of individual foraging site fidelity. An explanatory model was developed to determine parameters affecting the distance to cormorant foraging sites. The mean distance to foraging locations of tagged cormorants from the colony site was 2,920 m (SE ?? 180 m, max = 14,190 m), and 52% of the locations were within 2,000 m of the nesting island. No cormorant was observed making daily foraging trips to outside water bodies. Mean foraging distance was greater during morning than in the afternoon, and there was a significant effect of the time of day on distance. There was no significant effect of sex date, a seasonal measure on distance to foraging location. Individual cormorants exhibited fidelity to specific foraging sites. Most cormorants foraged in close proximity to the nesting island much of the time, while those detected further from the island tended to return repeatedly to the same locations. Ninety percent of the foraging locations were in water depths ???7.5 m, and most were in water 2.5-5 m deep. Compositional analysis of habitat use revealed a preference for these depths, along with substrates of cobble with rubble, and silt with clay.

  13. Foraging patterns of Caspian terns and double-crested cormorants in the Columbia River estuary

    USGS Publications Warehouse

    Lyons, Donald E.; Roby, D.D.; Collis, K.

    2007-01-01

    We examined spatial and temporal foraging patterns of Caspian terns and double-crested cormorants nesting in the Columbia River estuary, to potentially identify circumstances where juvenile salmonids listed under the U.S. Endangered Species Act might be more vulnerable to predation by these avian piscivores. Data were collected during the 1998 and 1999 breeding seasons, using point count surveys of foraging birds at 40 sites along the river's banks, and using aerial strip transect counts throughout the estuary for terns. In 1998, terns selected tidal flats and sites with roosting beaches nearby for foraging, making greater use of the marine/mixing zone of the estuary later in the season, particularly areas near the ocean jetties. In 1999, cormorants selected foraging sites in freshwater along the main channel with pile dikes present, particularly early in the season. Foraging trends in the other year for each species were generally similar to the above but usually not significant. During aerial surveys we observed 50% of foraging and commuting terns within 8 km of the Rice Island colony, and ??? 5% of activity occurred ??? 27 km from this colony in both years. Disproportionately greater cormorant foraging activity at pile dikes may indicate greater vulnerability of salmonids to predation at those features. Colony relocations to sites at sufficient distance from areas of relatively high salmonid abundance may be a straightforward means of reducing impacts of avian predation on salmonids than habitat alterations within the Columbia River estuary, at least for terns. ?? 2007 by the Northwest Scientific Association. All rights reserved.

  14. Mercury contamination in bank swallows and double-crested cormorants from the Carson River, Nevada

    SciTech Connect

    Kim, R.; Brewer, R.; Peterson, S.C.; Mach, C.

    1995-12-31

    An ecological risk assessment was performed in conjunction with a remedial investigation at the Carson River Mercury Site (CRMS) in northwestern Nevada. Large quantities of mercury used in the processing of gold and silver during mining operations in the mid to late 1800s are distributed throughout the Carson River ecosystem. Previous investigations indicated elevated levels of mercury in soil, sediment, water, and the aquatic food chain. Bird exposure to mercury was determined by measuring total mercury and monomethyl mercury in blood and feather samples from 15 unfledged double-crested cormorants (Phalacrocorax auritus), and in blood, feather, and liver samples from 18 juvenile bank swallows (Riparia riparia) at both the CRMS and uncontaminated background locations. Monomethyl mercury accounted for 90 to 98% of the total mercury in the samples. Total mercury concentrations in bird tissues collected at the CRMS were significantly higher than at background locations. Average total mercury concentrations (wet weight) for the swallow blood, liver, and feather samples collected at the CRMS were 2.63, 3.96, and 2.01 mg/kg, respectively; compared with 0.74, 1,03, and 1.84 mg/kg, respectively at the background area. Average total mercury concentrations for cormorant samples collected at the CRMS were 17.07 mg/kg for blood, and 105.1 1 mg/kg for feathers. Cormorant samples collected at the background location had average total mercury concentrations of 0.49 mg/kg for blood and 8.99 mg/kg for feathers. Results are compared with published residue-effects levels to evaluate avian risks.

  15. One Species, Three Pleistocene Evolutionary Histories: Phylogeography of the Italian Crested Newt, Triturus carnifex

    PubMed Central

    Canestrelli, Daniele; Salvi, Daniele; Maura, Michela; Bologna, Marco A.; Nascetti, Giuseppe

    2012-01-01

    Phylogeographic patterns of temperate species from the Mediterranean peninsulas have been investigated intensively. Nevertheless, as more phylogeographies become available, either unique patterns or new lines of concordance continue to emerge, providing new insights on the evolution of regional biotas. Here, we investigated the phylogeography and evolutionary history of the Italian crested newt, Triturus carnifex, through phylogenetic, molecular dating and population structure analyses of two mitochondrial gene fragments (ND2 and ND4; overall 1273 bp). We found three main mtDNA lineages having parapatric distribution and estimated divergence times between Late Pliocene and Early Pleistocene. One lineage (S) was widespread south of the northern Apennine chain and was further geographically structured into five sublineages, likely of Middle Pleistocene origin. The second lineage (C) was widespread throughout the Padano–Venetian plain and did not show a clear phylogeographic structure. The third lineage (N) was observed in only two populations located on western Croatia/Slovenia. Results of analysis of molecular variance suggested that partitioning populations according to the geographic distribution of these lineages and sublineages explains 76% of the observed genetic variation. The phylogeographic structure observed within T. carnifex and divergence time estimates among its lineages, suggest that responses to Pleistocene environmental changes in this single species have been as diverse as those found previously among several codistributed temperate species combined. Consistent with the landscape heterogeneity, physiographic features, and palaeogeographical evolution of its distribution range, these responses encompass multiple refugia along the Apennine chain, lowland refugia in large peri-coastal plains, and a ‘cryptic’ northern refugium. PMID:22848590

  16. Neural crest cell contribution to the developing circulatory system: implications for vascular morphology?

    PubMed

    Bergwerff, M; Verberne, M E; DeRuiter, M C; Poelmann, R E; Gittenberger-de Groot, A C

    1998-02-01

    In this study, the distribution patterns of neural crest (NC) cells (NCCs) in the developing vascular system of the chick were thoroughly studied and examined for a correlation with smooth muscle cell differentiation and vascular morphogenesis. For this purpose, we performed long-term lineage tracing using quail-chick chimera techniques and premigratory NCC infection with a replication-incompetent retrovirus containing the LacZ reporter gene in combination with immunohistochemistry. Results indicate that NCC deposition around endothelial tubes is influenced by anteroposterior positional information from the pharyngeal arterial system. NCCs were shown to be among the first cells to differentiate into primary smooth muscle cells of the arch arteries. At later stages, NCCs eventually differentiated into adventitial fibroblasts and smooth muscle cells and nonmuscular cells of the media and intima. NCCs were distributed in the aortic arch and pulmonary arch arteries and in the brachiocephalic and carotid arteries. The coronary and pulmonary arteries and the descending aorta, however, remained devoid of NCCs. A new finding was that the media of part of the anterior cardinal veins was also determined to be NC-derived. NC-derived elastic arteries differed from non-NC elastic vessels in their cellular constitution and elastic fiber organization, and the NC appeared not to be involved in designating a muscular or elastic artery. Boundaries between NC-infested areas and mesodermal vessel structures were mostly very sharp and tended to coincide with marked changes in vascular morphology, with the exception of an intriguing area in the aortic and pulmonary trunks. PMID:9468193

  17. Patterns of spatial overlap in a monogamous large rodent, the crested porcupine.

    PubMed

    Mori, Emiliano; Lovari, Sandro; Sforzi, Andrea; Romeo, Giorgia; Pisani, Caterina; Massolo, Alessandro; Fattorini, Lorenzo

    2014-09-01

    The crested porcupine Hystrix cristata is a large rodent which pairs for life. We studied the space use of 17 female and 9 male radio-tracked porcupines in an evergreen coastal woodland ("macchia", EW) and in an agricultural estate (AE), with special reference to the use of cultivations. Home range sizes of male porcupines (4.72-323.40) ranged around 114ha (median) during the warm period (April-September) and 162ha during the cold one (October-March). Home ranges of females (2.48-323.40) were c. 91ha during the warm period and c. 143ha during the cold one. Habitat composition and selection changed from the cold to the warm months, with porcupines being present in agricultural areas especially in the latter. Home range overlap between members of the same pair varied from 57% to 97% (median, 75%). Habitat selection was analyzed at the second (within study area) and at the third (within home range) order of selection. Within study areas, porcupines avoided cultivations and selected habitats with dense vegetation, providing cover and food. Within home ranges, in the warm period, porcupines selected agricultural areas in EW, where this habitat represented a minor portion of the study site. In that season, the Mediterranean "macchia" is a poor source of food, forcing porcupines to travel long distances to reach feeding sites. No significant difference of habitat selection within home ranges was detected between members of the same pair. Cultivations may play a key-role for porcupine survival, especially in poor habitats, as they provide abundant food resources in the warm period. PMID:25168817

  18. Reproductive success, developmental anomalies, and environmental contaminants in double-crested cormorants (Phalacrocorax auritus)

    SciTech Connect

    Larson, J.M.; Karasov, W.H.; Sileo, L.; Stromborg, K.L.; Giesy, J.P.; Jones, P.D.; Tillitt, D.E.; Verbrugge, D.A.; Hanbidge, B.A.

    1996-04-01

    To test an association between environmental contaminants and the prevalence of congenital anomalies in colonial waterbirds, the authors collected representative eggs for chemical analysis from double-crested cormorant nests at colonies in Lake Michigan, Wisconsin, USA, and Lake Winnipegosis, Manitoba, Canada, and periodically revisited the nests to determine the hatching success, survivorship of hatchlings, and number of deformed hatchlings in the remainder of each clutch. Total concentrations of polychlorinated biphenyls (PCBs) in eggs were determined by capillary gas chromatography. The combined activity of planar chlorinated hydrocarbons (PCHs) in the eggs was measured in an in vitro bioassay based on the induction of ethoxyresorufin-O-deethylase (EROD) activity in rat hepatoma cells. The combined EROD induction activity was expressed as 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TCDD-EQ). Total concentrations of PCBs and TCDD-EQ were seven to eight times greater in eggs from Lake Michigan (7.8 {micro}g/g and 138 pg/g, respectively) than in those from Lake Winnipegosis (1.0 {micro}g/g and 19 pg/g, respectively). The proportion of eggs hatching at the Lake Michigan colony (59%) was less (p < 0.05) than at Lake Winnipegosis (70%), and the prevalence of hatchlings with deformed bills was greater (p < 0.001) at Lake Michigan (0.79 vs. 0.06%). However, within the Lake Michigan colony, concentrations of PCBs and TCDD-EQ were not correlated with either hatching success or the occurrence of deformities in nestlings.

  19. E-cadherin is required for cranial neural crest migration in Xenopus laevis.

    PubMed

    Huang, Chaolie; Kratzer, Marie-Claire; Wedlich, Doris; Kashef, Jubin

    2016-03-15

    The cranial neural crest (CNC) is a highly motile and multipotent embryonic cell population, which migrates directionally on defined routes throughout the embryo, contributing to facial structures including cartilage, bone and ganglia. Cadherin-mediated cell-cell adhesion is known to play a crucial role in the directional migration of CNC cells. However, migrating CNC co-express different cadherin subtypes, and their individual roles have yet to be fully explored. In previous studies, the expression of individual cadherin subtypes has been analysed using different methods with varying sensitivities, preventing the direct comparison of expression levels. Here, we provide the first comprehensive and comparative analysis of the expression of six cadherin superfamily members during different phases of CNC cell migration in Xenopus. By applying a quantitative RT-qPCR approach, we can determine the copy number and abundance of each expressed cadherin through different phases of CNC migration. Using this approach, we show for the first time expression of E-cadherin and XB/C-cadherin in CNC cells, adding them as two new members of cadherins co-expressed during CNC migration. Cadherin co-expression during CNC migration in Xenopus, in particular the constant expression of E-cadherin, contradicts the classical epithelial-mesenchymal transition (EMT) model postulating a switch in cadherin expression. Loss-of-function experiments further show that E-cadherin is required for proper CNC cell migration in vivo and also for cell protrusion formation in vitro. Knockdown of E-cadherin is not rescued by co-injection of other classical cadherins, pointing to a specific function of E-cadherin in mediating CNC cell migration. Finally, through reconstitution experiments with different E-cadherin deletion mutants in E-cadherin morphant embryos, we demonstrate that the extracellular domain, but not the cytoplasmic domain, of E-cadherin is sufficient to rescue CNC cell migration in vivo

  20. Crested wheatgrass-cheatgrass seedling competition in a mixed-density design

    USGS Publications Warehouse

    Francis, Mark G.; Pyke, David A.

    1996-01-01

    Plant competition experiments have historically used designs that are difficult to interpret due to confounding problems. Recently, designs based on a 'response function' approach have been proposed and tested in various plant mixture settings. For this study, 3 species were used that are important in current revegetation practices in the Intermountain West. 'Nordan' (Agropyron desertorum [Fish. ex Link] Shult.) and 'Hycrest' (A. cristatum [L.] Gaertn. x desertorum) crested wheatgrass are commonly-used revegetation species on rangelands susceptible to cheatgrass (Bromus tectorum L.) invasion, although little quantitative data exist that compare their competitive abilities. We evaluated the competitive ability of Hycrest and Nordan seedlings in 2-species mixtures with cheatgrass in a greenhouse study. Linear and nonlinear models were developed for a range of densities (130- 520 seeds m-2) for each species to predict median above-ground biomass and tiller numbers and to further test the usefulness of this design for evaluating species to rehabilitate rangelands. In both experiments, increasing Hycrest and Nordan densities reduced their own biomass and tiller production while increasing Hycrest densities reduced cheatgrass biomass and tiller production. Nordan did not affect cheatgrass biomass and tiller production. However, increasing cheatgrass densities reduced Hycrest and Nordan biomass and tiller production, and its own biomass and tiller production. The competition index i.e. substitution rate, indicated that Hycrest seedlings were better competitors with cheatgrass than Nordan, although in all mixtures, cheatgrass plants were the superior competitors. Further field research using this design, where environmental inputs are less optimal and diverse, is needed to validate these results and to further evaluate the use of this approach in examining effects of intra- and interspecific competition.

  1. Rabconnectin-3a Regulates Vesicle Endocytosis and Canonical Wnt Signaling in Zebrafish Neural Crest Migration

    PubMed Central

    Tuttle, Adam M.; Hoffman, Trevor L.; Schilling, Thomas F.

    2014-01-01

    Cell migration requires dynamic regulation of cell–cell signaling and cell adhesion. Both of these processes involve endocytosis, lysosomal degradation, and recycling of ligand–receptor complexes and cell adhesion molecules from the plasma membrane. Neural crest (NC) cells in vertebrates are highly migratory cells, which undergo an epithelial–mesenchymal transition (EMT) to leave the neural epithelium and migrate throughout the body to give rise to many different derivatives. Here we show that the v-ATPase interacting protein, Rabconnectin-3a (Rbc3a), controls intracellular trafficking events and Wnt signaling during NC migration. In zebrafish embryos deficient in Rbc3a, or its associated v-ATPase subunit Atp6v0a1, many NC cells fail to migrate and misregulate expression of cadherins. Surprisingly, endosomes in Rbc3a- and Atp6v0a1-deficient NC cells remain immature but still acidify. Rbc3a loss-of-function initially downregulates several canonical Wnt targets involved in EMT, but later Frizzled-7 accumulates at NC cell membranes, and nuclear B-catenin levels increase. Presumably due to this later Wnt signaling increase, Rbc3a-deficient NC cells that fail to migrate become pigment progenitors. We propose that Rbc3a and Atp6v0a1 promote endosomal maturation to coordinate Wnt signaling and intracellular trafficking of Wnt receptors and cadherins required for NC migration and cell fate determination. Our results suggest that different v-ATPases and associated proteins may play cell-type-specific functions in intracellular trafficking in many contexts. PMID:24802872

  2. Coupled dynamics of territorial damselfishes and juvenile corals on the reef crest

    NASA Astrophysics Data System (ADS)

    Casey, J. M.; Choat, J. H.; Connolly, S. R.

    2015-03-01

    Territories of grazing fishes in the family Pomacentridae have been documented to cover a substantial proportion of shallow, exposed coral reef fronts, and these fishes can have profound effects on benthic community composition, including the recruitment and post-settlement survival of scleractinian corals. However, current studies of territorial grazer effects on corals have focused on back-reef habitats. Territorial damselfishes occur in distinct behavioural guilds ranging from indeterminate territorial grazers with thin algal turfs and low rates of territorial aggression to intensive territorial grazers with thick turfs and high rates of aggression. To determine the impact of territorial grazers on the establishment of juvenile corals, we surveyed the reef crest habitat of Lizard Island, Great Barrier Reef, using fixed transects to assess the effects of indeterminate and intensive territorial grazers on juvenile coral abundance and taxonomic composition. In addition, the turnover of territorial pomacentrids was monitored as well as the effects of turnover on juvenile coral assemblages. Intensive territorial grazers were associated with a significantly lower juvenile coral abundance (34 % decrease), but neither intensive nor indeterminate grazer territories impacted juvenile coral taxonomic composition. Over the course of 1 yr, there was a high rate of territorial turnover (39.7 %). Turnover from control plots to intensive damselfish territories was accompanied by a 44 % decrease in juvenile corals; conversely, turnover from intensive damselfish territories to control plots coincided with a 48 % increase in juvenile corals. These findings reveal two main conclusions. Firstly, the association between damselfish territories and the abundance and spatial turnover of juvenile corals strongly implies that territorial grazers have a negative effect on juvenile coral populations. Secondly, the unexpectedly high temporal turnover of damselfish territories indicates that

  3. Modeling the Effects of Climate Change on Whitebark Pine Along the Pacific Crest Trail

    NASA Astrophysics Data System (ADS)

    Anderson, R. S.; Nguyen, A.; Gill, N.; Kannan, S.; Patadia, N.; Meyer, M.; Schmidt, C.

    2012-12-01

    The Pacific Crest Trail (PCT), one of eight National Scenic Trails, stretches 2,650 miles from Mexico to the Canadian border. At high elevations along this trail, within Inyo and Sierra National Forests, populations of whitebark pine (Pinus albicaulis) have been diminishing due to infestation of the mountain pine beetle (Dendroctonus ponderosae) and are threatened due to a changing climate. Understanding the current and future condition of whitebark pine is a primary goal of forest managers due to its high ecological and economic importance, and it is currently a candidate for protection under the Endangered Species Act (ESA). Using satellite imagery, we analyzed the rate and spatial extent of whitebark pine tree mortality from 1984 to 2011 using the Landsat-based Detection of Trends in Disturbance and Recovery (LandTrendr) program. Climate data, soil properties, and biological features of the whitebark pine were incorporated in the Physiological Principles to Predict Growth (3-PG) model to predict future rates of growth and assess its applicability in modeling natural whitebark pine processes. Finally, the Random Forest algorithm was used with topographic data alongside recent and future climate data from the IPCC A2 and B1 climate scenarios for the years 2030, 2060, and 2090 to model the future distribution of whitebark pine. LandTrendr results indicate beetle related mortality covering 14,940 km2 of forest, 2,880 km2 of which are within whitebark pine forest. By 2090, our results show that under the A2 climate scenario, whitebark pine suitable habitat may be reduced by as much as 99.97% by the year 2090 within our study area. Under the B1 climate scenario, which has decreased CO2 emissions, 13.54% more habitat would be preserved in 2090.

  4. A biomimetic growth factor delivery strategy for enhanced regeneration of iliac crest defects.

    PubMed

    Huri, Pinar Yilgor; Huri, Gazi; Yasar, Umit; Ucar, Yurdanur; Dikmen, Nurten; Hasirci, Nesrin; Hasirci, Vasif

    2013-08-01

    The importance of provision of growth factors in the engineering of tissues has long been shown to control the behavior of the cells within the construct and several approaches were applied toward this end. In nature, more than one type of growth factor is known to be effective during the healing of tissue defects and their peak concentrations are not always simultaneous. One of the most recent strategies includes the delivery of a combination of growth factors with the dose and timing to mimic the natural regeneration cascade. The sequential delivery of bone morphogenetic proteins BMP-2 and BMP-7 which are early and late appearing factors during bone regeneration, respectively, was shown in vitro to enhance osteoblastic differentiation of bone marrow derived mesenchymal stem cells. In the present study, the aim was to study the effectiveness of this delivery strategy in a rabbit iliac crest model. 3D plotted poly(ε-caprolactone) scaffolds were loaded with BMP carrying nanoparticles to achieve: (a) single BMP-2 or BMP-7 delivery, and (b) their combined delivery in a simultaneous or (c) sequential (biomimetic) fashion. After eight weeks of implantation, computed tomography and biomechanical tests showed better mineralized matrix formation and bone-implant union strength at the defect site in the case of sequential delivery compared to single or simultaneous delivery modes. Bone mineral density (BMD) and push-out stress were: 33.65±2.25 g cm(-3) and 14.5±2.28 MPa, respectively, and almost 2.5 fold higher in comparison to those without growth factors (BMD: 14.14±1.21 g cm(-3); PS: 6.59±0.65 MPa). This study, therefore, supports those obtained in vitro and emphasizes the importance of mimicking the natural timing of bioavailability of osteogenic factors in improving the regeneration of critical-sized bone defects. PMID:23782488

  5. Trabecular Reorganization in Consecutive Iliac Crest Biopsies when Switching from Bisphosphonate to Strontium Ranelate Treatment

    PubMed Central

    Jobke, Björn; Burghardt, Andrew J.; Muche, Burkhard; Hahn, Michael; Semler, Jutta; Amling, Michael; Majumdar, Sharmila; Busse, Björn

    2011-01-01

    Background Several agents are available to treat osteoporosis while addressing patient-specific medical needs. Individuals' residual risk to severe fracture may require changes in treatment strategy. Data at osseous cellular and microstructural levels due to a therapy switch between agents with different modes of action are rare. Our study on a series of five consecutively taken bone biopsies from an osteoporotic individual over a six-year period analyzes changes in cellular characteristics, bone microstructure and mineralization caused by a therapy switch from an antiresorptive (bisphosphonate) to a dual action bone agent (strontium ranelate). Methodology/Principal Findings Biopsies were progressively taken from the iliac crest of a female patient. Four biopsies were taken during bisphosphonate therapy and one biopsy was taken after one year of strontium ranelate (SR) treatment. Furthermore, serum bone markers and dual x-ray absorptiometry measurements were acquired. Undecalcified histology was used to assess osteoid parameters and bone turnover. Structural indices and degree of mineralization were determined using microcomputed tomography, quantitative backscattered electron imaging, and combined energy dispersive x-ray/µ-x-ray-fluorescence microanalysis. Conclusions/Significance Microstructural data revealed a notable increase in bone volume fraction after one year of SR treatment compared to the bisphosphonate treatment period. Indices of connectivity density, structure model index and trabecular bone pattern factor were predominantly enhanced indicating that the architectural transformation from trabecular rods to plates was responsible for the bone volume increase and less due to changes in trabecular thickness and number. Administration of SR following bisphosphonates led to a maintained mineralization profile with an uptake of strontium on the bone surface level. Reactivated osteoclasts designed tunneling, hook-like intratrabecular resorption sites. The

  6. Colonizing while migrating: how do individual enteric neural crest cells behave?

    PubMed Central

    2014-01-01

    Background Directed cell migration is essential for normal development. In most of the migratory cell populations that have been analyzed in detail to date, all of the cells migrate as a collective from one location to another. However, there are also migratory cell populations that must populate the areas through which they migrate, and thus some cells get left behind while others advance. Very little is known about how individual cells behave to achieve concomitant directional migration and population of the migratory route. We examined the behavior of enteric neural crest-derived cells (ENCCs), which must both advance caudally to reach the anal end and populate each gut region. Results The behavior of individual ENCCs was examined using live imaging and mice in which ENCCs express a photoconvertible protein. We show that individual ENCCs exhibit very variable directionalities and speed; as the migratory wavefront of ENCCs advances caudally, each gut region is populated primarily by some ENCCs migrating non-directionally. After populating each region, ENCCs remain migratory for at least 24 hours. Endothelin receptor type B (EDNRB) signaling is known to be essential for the normal advance of the ENCC population. We now show that perturbation of EDNRB principally affects individual ENCC speed rather than directionality. The trajectories of solitary ENCCs, which occur transiently at the wavefront, were consistent with an unbiased random walk and so cell-cell contact is essential for directional migration. ENCCs migrate in close association with neurites. We showed that although ENCCs often use neurites as substrates, ENCCs lead the way, neurites are not required for chain formation and neurite growth is more directional than the migration of ENCCs as a whole. Conclusions Each gut region is initially populated by sub-populations of ENCCs migrating non-directionally, rather than stopping. This might provide a mechanism for ensuring a uniform density of ENCCs along the

  7. PCB126 Exposure Disrupts ZebraFish Ventricular and Branchial but Not Early Neural Crest Development

    PubMed Central

    Grimes, Adrian C.; Erwin, Kyle N.; Stadt, Harriett A.; Hunter, Ginger L.; Gefroh, Holly A.; Tsai, Huai-Jen; Kirby, Margaret L.

    2008-01-01

    We have used zebrafish and 3,3′,4,4′,5-pentachlorobiphenyl (PCB126) to investigate the developmental toxicity of polychlorinated biphenyls (PCBs) that exert their effects through the aryl hydrocarbon receptor (AHR). We found that cardiac and neural crest (NC)–derived jaw and branchial cartilages are specifically targeted early in development. The suite of malformations, which ultimately leads to circulatory failure, includes a severely dysmorphic heart with a reduced bulbus arteriosus and abnormal atrioventricular and outflow valve formation. Early NC migration and patterning of the jaw and branchial cartilages was normal. However, the jaw and branchial cartilages failed to grow to normal size. In the heart, the ventricular myocardium showed a reduction in cell number and size. The heart and jaw/branchial phenotype could be rescued by pifithrin-α, a blocker of p53. However, the function of pifithrin-α in this model may act as a competitive inhibitor of PCB at the AHR and is likely independent of p53. Morpholinos against p53 did not rescue the phenotype, nor were zebrafish with a mutant p53-null allele resistant to PCB126 toxicity. Morpholino knockdown of cardiac troponin T, which blocks the onset of cardiac function, prevented the PCB126-induced cardiac dysmorphogenesis but not the jaw/branchial phenotype. The cardiovascular characteristics appear to be similar to hypoplastic left heart syndrome (HLHS) and introduce the potential of zebrafish as a model to study this environmentally induced cardiovascular malformation. HLHS is a severe congenital cardiovascular malformation that has previously been linked to industrial releases of dioxins and PCBs. PMID:18660518

  8. Sonic hedgehog is a chemotactic neural crest cell guide that is perturbed by ethanol exposure.

    PubMed

    Tolosa, Ezequiel J; Fernández-Zapico, Martín E; Battiato, Natalia L; Rovasio, Roberto A

    2016-01-01

    Our aim was to understand the involvement of Sonic hedgehog (Shh) morphogen in the oriented distribution of neural crest cells (NCCs) toward the optic vesicle and to look for potential disorders of this guiding mechanism after ethanol exposure. In vitro directional analysis showed the chemotactic response of NCCs up Shh gradients and to notochord co-cultures (Shh source) or to their conditioned medium, a response inhibited by anti-Shh antibody, receptor inhibitor cyclopamine and anti-Smo morpholino (MO). Expression of the Ptch-Smo receptor complex on in vitro NCCs was also shown. In whole embryos, the expression of Shh mRNA and protein was seen in the ocular region, and of Ptch, Smo and Gli/Sufu system on cephalic NCCs. Anti-Smo MO or Ptch-mutated plasmid (Ptch1(Δloop2)) impaired cephalic NCC migration/distribution, with fewer cells invading the optic region and with higher cell density at the homolateral mesencephalic level. Beads embedded with cyclopamine (Smo-blocking) or Shh (ectopic signal) supported the role of Shh as an in vivo guide molecule for cephalic NCCs. Ethanol exposure perturbed in vitro and in vivo NCC migration. Early stage embryos treated with ethanol, in a model reproducing Fetal Alcohol Syndrome, showed later disruptions of craniofacial development associated with abnormal in situ expression of Shh morphogen. The results show the Shh/Ptch/Smo-dependent migration of NCCs toward the optic vesicle, with the support of specific inactivation with genetic and pharmacological tools. They also help to understand mechanisms of accurate distribution of embryonic cells and of their perturbation by a commonly consumed teratogen, and demonstrate, in addition to its other known developmental functions, a new biological activity of cellular guidance for Shh. PMID:26979762

  9. Fish losses to double-crested cormorant predation in Eastern Lake Ontario, 1992-97

    USGS Publications Warehouse

    Ross, Robert M.; Johnson, James H.

    1999-01-01

    We examined 4,848 regurgitated digestive pellets of double-crested cormorants (Phalacrocorax auritus) over a 6-year period (1992–97) to estimate annual predation on sport and other fishes in the eastern basin of Lake Ontario. We found more than 51,000 fish of 28 species. Using a model that incorporates annual colony nest counts; fledgling production rates; adult, immature, and young-of-year residence times (seasonal); estimates of mean number of fish per pellet and mean fish size; and a fecal pathway correction factor (4.0 percent), we estimate total annual number of fish consumed by cormorants in the eastern basin of Lake Ontario to range from 37 million to 128 million fish for 1993–97. This fish loss equates to an estimated 0.93 million to 3.21 million kg (mean 2.07 million kg) of fish consumed per year, principally alewife (Alosa pseudoharengus, 42.3 percent) and yellow perch (Perca flavescens, 18.4 percent). Forage fish (alewife, cyprinids, trout-perch [Percopsis omiscomaycus], and other minor components) accounted for 65 percent of the diet, and panfish contributed 34 percent of the diet for the 5-year period. Game fish were minor components of the diet, in view of an average estimated annual consumption of 900,000 smallmouth bass (Micropterus dolomieui, 1.1 percent) and 168,000 salmonines (mostly lake trout, Salvelinus namaycush, 0.2 percent). Cormorant predation on lake trout fingerlings stocked in May 1993 and June 1994 was estimated through the use of coded wire tag recoveries from pellets collected on Little Galloo Island 1 and 4 days after stocking events. We estimated losses of 13.6 percent and 8.8 percent, respectively, of the fish stocked for the two events, an average of 11.2 percent. Such losses may be reduced through alteration of existing stocking practices.

  10. Canine Epidermal Neural Crest Stem Cells: Characterization and Potential as Therapy Candidate for a Large Animal Model of Spinal Cord Injury

    PubMed Central

    Gericota, Barbara; Anderson, Joseph S.; Mitchell, Gaela; Borjesson, Dori L.; Sturges, Beverly K.; Nolta, Jan A.

    2014-01-01

    The discovery of multipotent neural crest-derived stem cells, named epidermal neural crest stem cells (EPI-NCSC), that persist postnatally in an easy-to-access location—the bulge of hair follicles—opens a spectrum of novel opportunities for patient-specific therapies. We present a detailed characterization of canine EPI-NCSC (cEPI-NCSC) from multiple dog breeds and protocols for their isolation and ex vivo expansion. Furthermore, we provide novel tools for research in canines, which currently are still scarce. In analogy to human and mouse EPI-NCSC, the neural crest origin of cEPI-NCSC is shown by their expression of the neural crest stem cell molecular signature and other neural crest-characteristic genes. Similar to human EPI-NCSC, cEPI-NCSC also expressed pluripotency genes. We demonstrated that cEPI-NCSC can generate all major neural crest derivatives. In vitro clonal analyses established multipotency and self-renewal ability of cEPI-NCSC, establishing cEPI-NCSC as multipotent somatic stem cells. A critical analysis of the literature on canine spinal cord injury (SCI) showed the need for novel treatments and suggested that cEPI-NCSC represent viable candidates for cell-based therapies in dog SCI, particularly for chondrodystrophic dogs. This notion is supported by the close ontological relationship between neural crest stem cells and spinal cord stem cells. Thus, cEPI-NCSC promise to offer not only a potential treatment for canines but also an attractive and realistic large animal model for human SCI. Taken together, we provide the groundwork for the development of a novel cell-based therapy for a condition with extremely poor prognosis and no available effective treatment. PMID:24443004

  11. Distribution of pluripotent neural crest cells in the embryo and the role of brain-derived neurotrophic factor in the commitment to the primary sensory neuron lineage.

    PubMed

    Sieber-Blum, M; Ito, K; Richardson, M K; Langtimm, C J; Duff, R S

    1993-02-01

    Many early migratory neural crest cells are pluripotent in the sense that their progeny are able to generate more than one differentiated phenotype (Sieber-Blum and Cohen, 1980, Dev. Biol. 80:95-106; Baroffio, Dupin, and Le Douarin, 1988, Proc. Natl. Acad. Sci. USA 85:5325-5329; Bronner-Fraser and Fraser, 1988, Nature 335:161-164; Sieber-Blum, 1989a, Science 243:1608-1611; Ito and Sieber-Blum, 1991, Dev. Biol. 148:95-106). At trunk levels, the neural crest contains two classes (Sieber-Blum and Cohen, 1980) and at posterior rhombencephalic levels, three different classes of pluripotent cells (Ito and Sieber-Blum, 1991). We investigated cell differentiation by in vitro clonal analysis to determine when in development the pool of pluripotent neural crest cells becomes exhausted. The data suggest that different classes of pluripotent cells, precursor cells with more restricted developmental potentials, and apparently committed cells, exist at sites of advanced migration (posterior branchial arches) and even at target sites of neural crest cell differentiation [posterior branchial arches, dorsal root ganglia (DRG), sympathetic ganglia (SG), and epidermal ectoderm]. Some putative classes of pluripotent cells persist well into the second half of embryonic development. These observations have implications for our understanding of the mechanisms that control neural crest cell migration and differentiation. They support the idea that cues originating from the microenvironment affect differentiation of pluripotent neural crest cells. One such signal appears to be brain-derived neurotrophic factor (BDNF). In the presence of BDNF, but not nerve growth factor (NGF), there is a significant increase in the number of neural crest cells per colony that express a sensory neuron-specific marker. Because this increase is not accompanied by a corresponding increase in the total number of cells per colony, this suggests that BDNF plays a role in cell type specification. PMID:8445386

  12. Efficacy of Crest Herbal Toothpaste in “Clearing Internal Heat”: A Randomized, Double-Blind Clinical Study

    PubMed Central

    Chen, Jia-Xu; Liu, Yue-Yun; Wang, Shao-Xian; Li, Xiao-Hong

    2013-01-01

    Objective. Evaluation of the efficacy of Crest Herbal Crystal Toothpaste in “clearing internal heat.” Methods. This was a randomized, double-blind, controlled parallel design clinical test of a product that was already on the market. 72 subjects were randomly assigned to control group (group A with Colgate Herbal Salty Toothpaste) or treatment group (group B with Crest Herbal Crystal Toothpaste) with ratio of 1 : 2. Subjects were instructed to brush with 1g toothpaste for 2 minutes each time, 2 times per day in a 4-aweek test period; measurement with the rating scale on the efficacy of “clearing internal heat” for the herbal toothpaste was done at baseline, 2 weeks, and 4 weeks of toothpaste usage. Results. The rating scale on efficacy of “clearing internal heat” for the herbal toothpaste reveals that the primitive points of 72-case intention-to-treat (ITT) analysis and 67-case per-protocol (PP) analysis for subjects in group A and subjects in group B were found to be reduced progressively with statistical significance (P < 0.05). The overall effective rates for group A and group B were, respectively, 62.50%, 56.25% (ITT) and 62.50%, 60.64% (PP). The statistical results indicated that the symptoms of fire-heat for both groups of subjects have been improved after application of toothpaste. Conclusion. The efficacy of Crest Herbal Crystal Toothpaste in “clearing internal heat” was confirmed by the trial as compared to Colgate Herbal Salty Toothpaste. And its efficacy was objectively evaluated by the rating scale on efficacy of “clearing internal heat.” PMID:24228064

  13. Spatial ecology of the critically endangered Fijian crested iguana, Brachylophus vitiensis, in an extremely dense population: implications for conservation.

    PubMed

    Morrison, Suzanne F; Biciloa, Pita; Harlow, Peter S; Keogh, J Scott

    2013-01-01

    The Critically Endangered Fijian crested iguana, Brachylophus vitiensis, occurs at extreme density at only one location, with estimates of >10,000 iguanas living on the 70 hectare island of Yadua Taba in Fiji. We conducted a mark and recapture study over two wet seasons, investigating the spatial ecology and intraspecific interactions of the strictly arboreal Fijian crested iguana. This species exhibits moderate male-biased sexual size dimorphism, which has been linked in other lizard species to territoriality, aggression and larger male home ranges. We found that male Fijian crested iguanas exhibit high injury levels, indicative of frequent aggressive interactions. We did not find support for larger home range size in adult males relative to adult females, however male and female residents were larger than roaming individuals. Males with established home ranges also had larger femoral pores relative to body size than roaming males. Home range areas were small in comparison to those of other iguana species, and we speculate that the extreme population density impacts considerably on the spatial ecology of this population. There was extensive home range overlap within and between sexes. Intersexual overlap was greater than intrasexual overlap for both sexes, and continuing male-female pairings were observed among residents. Our results suggest that the extreme population density necessitates extensive home range overlap even though the underlying predictors of territoriality, such as male biased sexual size dimorphism and high aggression levels, remain. Our findings should be factored in to conservation management efforts for this species, particularly in captive breeding and translocation programs. PMID:24019902

  14. Epigenetic Marks Define the Lineage and Differentiation Potential of Two Distinct Neural Crest-Derived Intermediate Odontogenic Progenitor Populations

    PubMed Central

    Gopinathan, Gokul; Kolokythas, Antonia

    2013-01-01

    Epigenetic mechanisms, such as histone modifications, play an active role in the differentiation and lineage commitment of mesenchymal stem cells. In the present study, epigenetic states and differentiation profiles of two odontogenic neural crest-derived intermediate progenitor populations were compared: dental pulp (DP) and dental follicle (DF). ChIP on chip assays revealed substantial H3K27me3-mediated repression of odontoblast lineage genes DSPP and dentin matrix protein 1 (DMP1) in DF cells, but not in DP cells. Mineralization inductive conditions caused steep increases of mineralization and patterning gene expression levels in DP cells when compared to DF cells. In contrast, mineralization induction resulted in a highly dynamic histone modification response in DF cells, while there was only a subdued effect in DP cells. Both DF and DP progenitors featured H3K4me3-active marks on the promoters of early mineralization genes RUNX2, MSX2, and DLX5, while OSX, IBSP, and BGLAP promoters were enriched for H3K9me3 or H3K27me3. Compared to DF cells, DP cells expressed higher levels of three pluripotency-associated genes, OCT4, NANOG, and SOX2. Finally, gene ontology comparison of bivalent marks unique for DP and DF cells highlighted cell–cell attachment genes in DP cells and neurogenesis genes in DF cells. In conclusion, the present study indicates that the DF intermediate odontogenic neural crest lineage is distinguished from its DP counterpart by epigenetic repression of DSPP and DMP1 genes and through dynamic histone enrichment responses to mineralization induction. Findings presented here highlight the crucial role of epigenetic regulatory mechanisms in the terminal differentiation of odontogenic neural crest lineages. PMID:23379639

  15. Relationship of bone mineralization density distribution (BMDD) in cortical and cancellous bone within the iliac crest of healthy premenopausal women.

    PubMed

    Misof, B M; Dempster, D W; Zhou, Hua; Roschger, P; Fratzl-Zelman, N; Fratzl, P; Silverberg, S J; Shane, E; Cohen, A; Stein, E; Nickolas, T L; Recker, R R; Lappe, J; Bilezikian, J P; Klaushofer, K

    2014-10-01

    Bone mineralization density distribution (BMDD) is an important determinant of bone mechanical properties. The most available skeletal site for access to the BMDD is the iliac crest. Compared to cancellous bone much less information on BMDD is available for cortical bone. Hence, we analyzed complete transiliac crest bone biopsy samples from premenopausal women (n = 73) aged 25-48 years, clinically classified as healthy, by quantitative backscattered electron imaging for cortical (Ct.) and cancellous (Cn.) BMDD. The Ct.BMDD was characterized by the arithmetic mean of the BMDD of the cortical plates. We found correlations between Ct. and Cn. BMDD variables with correlation coefficients r between 0.42 and 0.73 (all p < 0.001). Additionally to this synchronous behavior of cortical and cancellous compartments, we found that the heterogeneity of mineralization densities (Ct.Ca(Width)), as well as the cortical porosity (Ct.Po) was larger for a lower average degree of mineralization (Ct.Ca(Mean)). Moreover, Ct.Po correlated negatively with the percentage of highly mineralized bone areas (Ct.Ca(High)) and positively with the percentage of lowly mineralized bone areas (Ct.Ca(Low)). In conclusion, the correlation of cortical with cancellous BMDD in the iliac crest of the study cohort suggests coordinated regulation of bone turnover between both bone compartments. Only in a few cases, there was a difference in the degree of mineralization of >1wt % between both cortices suggesting a possible modeling situation. This normative dataset of healthy premenopausal women will provide a reference standard by which disease- and treatment-specific effects can be assessed at the level of cortical bone BMDD. PMID:25134800

  16. Immunohistochemical localization of irisin in skin, eye, and thyroid and pineal glands of the crested porcupine (Hystrix cristata).

    PubMed

    Gençer Tarakçı, B; Girgin, A; Timurkaan, S; Yalçın, M H; Gür, F M; Karan, M

    2016-08-01

    Irisin was first identified in muscle cells. We detected irisin immunoreactivity in various organs of the crested porcupine (Hystrix cristata). In the epidermis, irisin immunoreactivity was localized mainly in stratum basale, stratum spinosum and stratum granulosum layers; immunoreactivity was not observed in the stratum corneum. In the dermis, irisin was found in the external and internal root sheath, cortex and medulla of hair follicles, and in sebaceous glands. Irisin immunoreactivity was found in the neural retina and skeletal muscle fibers associated with the eye. The pineal and thyroid glands also exhibited irisin immunoreactivity. PMID:27192184

  17. Assessment of Polycyclic Aromatic Hydrocarbon Contamination of Breeding Pools Utilized by the Puerto Rican Crested Toad, Peltophryne lemur

    PubMed Central

    Gjeltema, Jenessa; Stoskopf, Michael; Shea, Damian; De Voe, Ryan

    2012-01-01

    Habitat preservation and management may play an important role in the conservation of the Puerto Rican crested toad, Peltophryne lemur, due to this species' small geographic range and declining native wild population. Bioavailable water concentrations of Polycyclic Aromatic Hydrocarbon (PAH) contaminants within breeding pools at 3 sites were established using Passive Sampling Devices (PSDs) and gas chromatography-mass spectrometry (GC/MS). A more diverse population of PAH analytes were found in higher concentrations at the breeding site that allowed direct vehicular access, but calculated risk quotients indicated low risk to toad reproduction associated with the current PAH analyte levels. PMID:23762634

  18. Characteristics of short-crested waves and currents behind offshore man-made island type power plant

    SciTech Connect

    Ikeno, Masaaki; Kajima, Ryoichi; Matsuyama, Masafumi; Sakakiyama, Tsutomu

    1995-12-31

    This paper describes the diffracted waves with breaking and the nearshore currents caused by short-crested waves, behind a man-made island, on which nuclear power plants are constructed. Firstly, hydraulic model tests with a multi-directional wave maker were performed. Effects of the irregularity and directional spreading of waves, and the effects of cooling water intake flow on diffracted waves and nearshore currents behind a man-made island, were investigated experimentally. Secondly, a numerical model was developed to simulate deformation of multi-directional irregular waves and nearshore currents. The validity of the numerical model was verified through comparison with the experimental results.

  19. Which spinal levels are identified by palpation of the iliac crests and the posterior superior iliac spines?

    PubMed Central

    Chakraverty, Robin; Pynsent, Paul; Isaacs, Karen

    2007-01-01

    The line joining the superior aspect of the iliac crests posteriorly (the intercristal line) is commonly stated to cross the midline at the L4 or L4–5 spinal level on imaging. This study aimed to assess the spinal level identified through palpation of surface anatomy (iliac crests and posterior superior iliac spines) in adults and the level of agreement compared with the intercristal line identified through imaging. The study participants included consecutive adult patients undergoing prone fluoroscopically guided spinal injections for chronic low back pain at the Royal Orthopaedic Hospital, Birmingham, between April and July 2004. Prior to fluoroscopic imaging, each patient's surface anatomy was palpated by two examiners and lines created to form the palpated intercristal line and the posterior superior iliac spine line. Following imaging, the mid-line spinal levels identified by these palpated lines were recorded and the level of agreement (kappa coefficient) with the intercristal line formed by imaging of the iliac crests was assessed. The results showed that although the L4 or L4–5 spinal levels were identified on imaging of the intercristal line in 86.7% of 75 patients (49 female), the intercristal line formed through palpation tended to identify higher levels; the L3 or L3–4 spinal levels in 77.3% of cases and more commonly in females than in males (85.7 vs. 61.5%) and in patients with higher body mass indices. The level of agreement between the two lines was poor (κ = 0.05). The posterior superior iliac spine line identified the S2 spinous process in 51% and the S1 in 44% of 60 (45 female) patients. The results suggest that formation of the intercristal line by palpation of the iliac crests identifies different spinal levels to those identified by imaging and that both methods should be regarded as different instruments. In the clinical situation, it may be more appropriate to consider that palpation of the intercristal line is a guide for identifying

  20. Neural crest-mediated bone resorption is a determinant of species-specific jaw length

    PubMed Central

    Ealba, Erin L.; Jheon, Andrew H.; Hall, Jane; Curantz, Camille; Butcher, Kristin D.; Schneider, Richard A.

    2015-01-01

    Precise control of jaw length during development is crucial for proper form and function. Previously we have shown that in birds, neural crest mesenchyme (NCM) confers species-specific size and shape to the beak by regulating molecular and histological programs for the induction and deposition of cartilage and bone. Here we reveal that a hitherto unrecognized but similarly essential mechanism for establishing jaw length is the ability of NCM to mediate bone resorption. Osteoclasts are considered the predominant cells that resorb bone, although osteocytes have also been shown to participate in this process. In adults, bone resorption is tightly coupled to bone deposition as a means to maintain skeletal homeostasis. Yet, the role and regulation of bone resorption during growth of the embryonic skeleton have remained relatively unexplored. We compare jaw development in short-beaked quail versus long-billed duck and find that quail have substantially higher levels of enzymes expressed by bone-resorbing cells including tartrate-resistant acid phosphatase (TRAP), Matrix metalloproteinase 13 (Mmp13), and Mmp9. Then, we transplant NCM destined to form the jaw skeleton from quail to duck and generate chimeras in which osteocytes arise from quail donor NCM and osteoclasts come exclusively from the duck host. Chimeras develop quail-like jaw skeletons coincident with dramatically elevated expression of TRAP, Mmp13, and Mmp9. To test for a link between bone resorption and jaw length, we block resorption using a bisphosphonate, osteoprotegerin protein, or an MMP13 inhibitor, and this significantly lengthens the jaw. Conversely, activating resorption with RANKL protein shortens the jaw. Finally, we find that higher resorption in quail presages their relatively lower adult jaw bone mineral density (BMD) and that BMD is also NCM-mediated. Thus, our experiments suggest that NCM not only controls bone resorption by its own derivatives but also modulates the activity of mesoderm